JP2010069205A - Cloth cutting device of hole stitching machine - Google Patents

Abstract

An appropriate pressing force is easily set without impairing cycle time.
A knife 32, a knife receiver 31, a moving mechanism 35 for moving the knife or the knife receiver, a pulse motor 34 serving as a moving drive source of the knife or the knife receiver, and a rotation amount detection for detecting the rotation amount of the pulse motor. Unit 55 and a control unit 50 for controlling the pulse motor. The control unit performs control to switch the movement of the knife or the knife receiving unit from the middle to the low speed, and the deviation of the pulse motor becomes the set value during the low speed movement. If the deviation determining means determines that the pulse motor is disconnected, the cutting control means 50c stops the driving of the pulse motor, and the current control means 50c limits the current value applied to the pulse motor to a lower value when moving at a low speed than when moving at a high speed. .
[Selection] Figure 11

Description

  The present invention relates to a cloth cutting device for an eyelet sewing machine that forms a hole such as a button hole in a workpiece such as a cloth.

2. Description of the Related Art An electronic eyelet-holed sewing machine is known as a sewing machine that performs overlock sewing on a button-shaped buttonhole portion on a cloth.
The sewing machine has a needle bar up-and-down mechanism provided with a sewing needle, a needle swinging mechanism that swings the needle bar to the left and right, a looper mechanism that is arranged to face the lower side of the needle bar, and the like. The sewing machine has a sewing machine driving mechanism that moves up and down and swings left and right and simultaneously drives the looper mechanism. In addition, it has a cloth feed mechanism for holding the cloth and feeding it in the front / rear / left / right direction, and a turning mechanism for turning the needle bar and the looper mechanism. The sewing machine driving mechanism, the cloth feeding mechanism, and the turning mechanism The buttonhole of the shape can be stitched.
In addition, this sewing machine has a cloth cutting mechanism that presses and cuts the cloth with a knife and a knife receiver to form a button hole in the cloth. A button hole can be formed inside.
The cloth cutting mechanism includes a cloth cutting control mechanism using a pulse motor as a drive source, and the cloth cutting control mechanism drives the pulse motor to drive either the knife or the knife receiver (number of pulse outputs). ) And driving speed (pulse output frequency) are controlled (for example, refer to Patent Document 1).

A cloth cutting control mechanism for storing and changing a plurality of correction data for switching the pressing force during cloth cutting is also known (see, for example, Patent Document 2).
JP 2001-334088 A JP 2002-200377 A

By the way, since the conventional cloth cutting control mechanism generally performs pulse motor drive by open loop control, a pulse output capable of applying an appropriate pressing force to the cloth according to the type of cloth to be cut, the size of the button hole, etc. It is necessary to set the number in advance. For this reason, an appropriate number of pulse outputs corresponding to the cloth type or the like has to be set by trial and error, and the working efficiency is significantly reduced.
In addition, it is not possible to know how much pressure is actually applied only by setting the number of pulse outputs. Therefore, emphasis is placed on the certainty of cutting, and generally the pressure is higher than the appropriate pressure. The number of pulse outputs has been set. For this reason, an excessive impact is generated in the knife, and there is a problem that the knife is lost or the life of the knife or the knife receiver is shortened. In the worst case, there is also a problem that the step-out of the pulse motor occurs.

  In order to prevent such a pulse motor from stepping out without impairing the cycle time associated with cloth cutting, conventionally, the cloth cutting knife motor is driven at high speed to the vicinity of the matching position between the cloth cutting knife and the knife receiver, Operation control was performed to switch the drive from near to low speed. In the case of such control, specifically, the number of pulses in the low speed section is stored as a knife adjustment value, and a plurality of knife adjustment values are set or stored for each of a plurality of knife receivers or cloth materials. It is conceivable to select an appropriate item.

  However, the knife receiver needs to be replaced every time the cloth cutting length is changed (see FIG. 3). In addition, since the scalpel mark is attached to the scalpel when it is used, if the sharpness is poor, the thickness of the scalpel rest is reduced by polishing the scalpel receiving surface so that it is flat. The knife adjustment amount is a value that takes into account the thickness variation of the knife receiver and the pushing amount to obtain the pressing force according to the cloth thickness and material. It was necessary to set, and setting an appropriate value required skill.

  An object of the present invention is to provide a cloth cutting device capable of easily obtaining an appropriate pressing force without impairing cycle time.

  According to the first aspect of the present invention, a knife having a cutting edge, a knife receiver that presses and cuts a cloth so as to be sandwiched in cooperation with the knife, and either the knife or the knife receiver is in contact with the other. When the moving mechanism that moves away, the pulse motor that is the driving source of the moving movement of the knife or the knife receiver by the moving mechanism, and one of the knife or the knife receiver is moving toward the other, Eyelet provided with a control unit that controls the pulse motor so as to cut the cloth by moving one of the knife or the knife receiver at a predetermined low speed from a position before the knife blade edge that matches the knife receiver The cloth cutting device for an overlock sewing machine includes a rotation amount detection unit that detects a rotation amount of the pulse motor, and the control unit determines a current value to be supplied to the pulse motor during the low-speed movement. Current control means for limiting the current to a lower limit, and deviation determination for determining whether a deviation between a value detected by the rotation amount detection unit and a command value to the pulse motor is greater than or equal to a predetermined set value during the low-speed movement. And a cutting control means for controlling the pulse motor so as to stop one movement of the knife or the knife receiver when the deviation is judged to be greater than or equal to the set value by the deviation judging means, It is characterized by having.

  The invention described in claim 2 has the same configuration as that of the invention described in claim 1, and further includes a pressing force setting means for setting a pressing force for cloth cutting, and a storage means for storing the setting pressing force, The current control means determines a limit value of a maximum current value according to the set pressing force.

  The invention described in claim 3 has the same configuration as that of the invention described in claim 1 or 2, and the control unit is configured to maintain the pressing force of cloth cutting for a predetermined time after stopping by the cutting control means. It controls the energization to the pulse motor.

In the invention according to claim 1, when moving toward the other one of the knife or the knife receiver, the knife edge of the knife moves one of the knife or the knife receiver at a predetermined low speed from a position in front of the matching with the knife receiver, During the low-speed movement, the deviation judgment means monitors the deviation between the detection value of the rotation detection unit and the motor command value, and when it reaches a certain value, the cutting control means stops the movement of the knife and the knife receiver at low speed. The cloth can be cut with a constant pressing force according to the deviation, and it is possible to easily obtain the appropriate pressing force without performing complicated setting work that requires skill to determine the appropriate knife adjustment value. Become. In addition, in such a control, movement control is performed mainly based on the deviation that occurs when the knife and knife receiver are matched, so even if there is a variation in the size, amount of wear, etc. of each knife receiver, the pressing force can be reduced. It becomes possible to make it constant.
Furthermore, since the current control means reduces the current value supplied to the pulse motor at a low speed, the output torque of the pulse motor is also reduced, the contact pressure when the knife and the knife receiver are matched is relaxed, and mutual damage is prevented. At the same time, it is possible to avoid motor step-out.

  According to the second aspect of the present invention, the limit value of the maximum current value is determined according to the set value of the pressing force for cloth cutting, so that the torque of the pulse motor can be arbitrarily set, and the pressing force of the knife or the knife receiver Can be set finely, and a more appropriate pressing force can be obtained.

  According to the invention of claim 3, since the pressing force of the cloth cutting, that is, the pressing force of the knife receiver against the knife is maintained for a predetermined time even after the movement of the knife and the knife receiver at a low speed is stopped, the cloth with time elapses. Can wait for the disconnect.

(Overall configuration of the eyelet hole sewing machine)
A cloth cutting device 30 according to an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the eyelet sewing machine 1 provided with a cloth cutting device 30 (shown in FIG. 2) has a basic configuration as a sewing machine that performs eyelet sewing. The eyelet sewing machine 1 includes a bed portion 2 having a substantially rectangular box shape, a vertical body portion 3 provided at the rear portion of the bed portion 2, and an arm portion provided to extend forward from the upper portion of the vertical body portion 3. 4, and a sewing machine table on which the sewing machine frame 5 is placed.

A needle bar 10 having a sewing needle 6 at its lower end is provided at the distal end of the arm 4 so as to be able to move up and down and swing left and right. Further, the bed portion 2 is provided with a looper base 11 having a looper portion 11a having a looper (not shown) facing the needle bar 10 and a spreader (not shown) for assisting the looper at an upper portion. Yes. In the sewing machine frame 5, there are provided drive mechanisms (not shown) for moving the needle bar 10 up and down and left and right and driving the looper and spreader in synchronization therewith.
A feed base 18 (shown in cross section in FIG. 1) on which cloth is set is provided on the upper surface portion of the bed portion 2, and a pair of cloths for pressing the cloth is provided on the upper surface portion of the feed base 18. A presser foot 19 is provided. The feed base 18 has a thin rectangular box shape with an open lower surface as a whole, and an upper opening is provided on the upper surface between the pair of cloth pressers 19 in the front-rear direction. The feed base 18 is horizontally moved by a feed mechanism (not shown) provided in the bed portion 2.

  Further, the eyelet hole sewing machine 1 is provided with a cloth cutting device 30 for making eyelet holes in the cloth. The cloth cutting device 30 will be described later. In the eyelet sewing machine 1, the cloth cutting device 30 forms the eyelet hole in the cloth, and the looper is driven in accordance with the vertical movement and the needle swinging operation of the needle bar 10, and the sewing needle 6 and the looper are moved. By cooperating, the garment is stitched around the eyelet hole.

(Cloth cutting device)
Next, the cloth cutting device 30 will be described. As shown in FIG. 2, the cloth cutting device 30 is mainly disposed with a knife receiver 31 (also shown in FIG. 1) corresponding to the shape of the eyelet hole and the knife receiver 31, and a cutting edge at the upper end portion. The formed knife 32, a drive shaft 33 that is rotatably provided, a pulse motor 34 that rotationally drives the drive shaft 33, and the knife receiver 31 is moved toward and away from the knife 32 by the rotational movement of the drive shaft 33. And a moving mechanism 35 to be configured. In FIG. 2, for the sake of simplicity, the main components of the eyelet-holed sewing machine 1 are not shown.

  The pulse motor 34 has a resolution of, for example, 400 divisions, and is fixedly provided in the bed portion 2 on the vertical trunk portion 3 side. The pulse motor 34 is provided with an encoder (rotation amount detector) 55 having a resolution of, for example, 400, for detecting the rotation amount of the pulse motor 34 (see FIG. 4). The output shaft of the pulse motor 34 faces upward. A motor gear 36 having the output shaft as a rotation shaft is fixedly provided on the output shaft of the pulse motor 34. Further, a ball screw member 37 extending vertically is provided in the vertical body portion 3, and a screw groove is formed on the outer periphery of the ball screw member 37. The ball screw member 37 is supported by a bearing (not shown) fixed to the bed part 2 or the arm part 4 so as to be rotatable about its axis. Accordingly, the left and right and vertical movements of the ball screw member 37 are suppressed and only the rotation is performed.

  A gear 38 whose rotation axis is the rotation axis of the ball screw member 37 is fixedly provided at the lower end of the ball screw member 37, and the gear 38 is engaged with the motor gear 36. Therefore, when the pulse motor 34 is driven to rotate, the ball screw member 37 rotates.

  A housing 39 is disposed in the vertical body 3, and a nut (not shown) is fixedly provided in the housing 39. The nut is engaged with the ball screw member 37. Thereby, the housing 39 moves up and down as the ball screw member 37 rotates. Note that a shaft (not shown) extending vertically is fixedly provided in the vertical body portion 3, and this shaft penetrates the housing 39. The housing 39 slides up and down with respect to this shaft. It is free. Therefore, since this shaft suppresses rotation of the housing 39, the housing 39 moves up and down smoothly.

  The housing 39 is provided with a link mechanism 40 including links 41 and 41 and a lever 42. The lever 42 has a bifurcated tip and is substantially Y-shaped. One end of each link 41 is connected to the tip of each of the levers 42 so as to be rotatable around the rotation axis in the extending direction of the arm 4. The other end portion of the link 41 is connected to the housing 39 so as to be rotatable around the rotation axis in the extending direction of the arm portion 4.

  A drive shaft 33 extending in the extending direction of the arm portion 4 is provided in the arm portion 4 so as to be rotatable around a rotating shaft in the extending direction. A base end portion of the lever 42 is fixedly provided at an end portion of the drive shaft 33 on the vertical body portion 3 side. Therefore, when the pulse motor 34 is driven to rotate, the ball screw member 37 rotates, and the housing 39 moves up and down by the rotation of the ball screw member 37. Then, the link mechanism 40 is actuated by the vertical movement of the housing 39, whereby the drive shaft 33 rotates.

  The moving mechanism 35 includes a linear motion gear 44 provided at the other end of the drive shaft 33 and a linear motion shaft 45 that meshes with the linear motion gear 44. The direct acting gear 44 is provided on the drive shaft 33 so that the rotation axis of the drive shaft 33 is an axis. The linear motion shaft 45 extends in the vertical direction and is provided so as to be movable up and down with respect to the arm portion 4. A rack portion 45a is formed on the outer periphery of the linear motion shaft 45, and the linear motion gear 44 meshes with the rack portion 45a. That is, the moving mechanism 35 is a pinion rack mechanism, and the linear motion shaft 45 moves up and down when the linear motion gear 44 rotates together with the drive shaft 33. The linear motion shaft 45 protrudes from the arm portion 4 to the lower side of the arm portion 4. The linear motion shaft 45 is supported on the arm portion 4 by a support member (not shown), and this support member inhibits the lateral motion, the longitudinal motion, and the rotational motion of the linear motion shaft 45. Therefore, the linear motion shaft 45 can move up and down stably.

And the female receptacle 31 is attached to the lower end part of the linear motion shaft 45 so that replacement | exchange is possible. As shown in FIG. 2, a scalpel 32 is detachably attached to the bed portion 2 so as to face the scalpel receiver 31. As shown in FIG. 3, the knife 32 has one end portion 32a formed in an annular shape and the other end portion 32b formed in a linear shape.
On the other hand, the knife receiver 31 is formed in a shape in which one end portion 32a of the knife 32 and a part of the other end portion 32b can contact each other. Here, as shown in FIGS. 3A to 3C, S knife, M size, and L size different contact lengths with the other end 32b of the knife 32 are used for the knife receiver 31. Thus, the female receiver 31 having a size corresponding to the cloth cutting length is attached to the bed portion 2.

  According to the above configuration, when the drive shaft 33 is rotated by the pulse motor 34, the knife receiver 31 moves up and down together with the linear motion shaft 45. In the following, for the sake of simplicity, it is assumed that when the pulse motor 34 is rotationally driven in the forward direction, the knife receiver 31 is lowered and the knife receiver 31 moves toward the knife 32, and the motor is moved in the reverse direction. When rotationally driven, the knife receiver 31 rises and the knife receiver 31 moves in a direction away from the knife 32. The forward / reverse movement of the pulse motor 34 and the vertical movement of the knife receiver 31 may be reversed.

  In the cloth cutting device 30, when a cloth is interposed between the knife receiver 31 and the knife 32 in a separated state, the pulse motor 34 rotates forward so that the knife receiver 31 descends toward the knife 32, and the knife receiver A pressing force for cutting is applied to the cloth sandwiched between 31 and the knife 32. Thereafter, the pulse motor 34 further rotates in the forward direction, so that the knife receiver 31 presses the knife 32. Accordingly, the knife receiver 31 presses the cloth so as to be pinched in cooperation with the knife 32, and the cloth is cut when the knife receiver 31 and the knife 32 are matched. When the eyelet is formed in the cloth, the pulse motor 34 is driven to rotate in the reverse direction, and the knife receiver 31 is raised. When the origin position sensor (not shown) is turned ON, the knife receiver 31 that continues to rise stops at the origin position that is the highest rise position of the knife receiver 31.

(Sewing machine control system)
FIG. 4 is a block diagram showing a main control configuration of the eyelet hole sewing machine 1. As shown in FIG. 4, the eyelet sewing machine 1 is provided with a control unit 50 that controls the operation of the cloth cutting device 30 as well as the operation of the eyelet sewing machine 1. The control unit 50 includes a spindle motor drive circuit 51b for driving the spindle motor 51a of the sewing machine, an I / F 51c for connecting the drive circuit 51b to the CPU 50c of the control unit 50, and an X axis provided in the feed mechanism. X-axis motor drive circuit 52b for driving the motor 52a, I / F 52c for connecting the drive circuit 52b to the CPU 50c, and Y-axis motor drive for driving the Y-axis motor 53a provided in the feed mechanism A circuit 53b, an I / F 53c for connecting the driving circuit 53b to the CPU 50c, a turning motor driving circuit 54b for driving a turning motor 54a for turning the needle bar 10 and the looper portion 11a, and the driving circuit 54b. I / F 54c for connecting to the CPU 50c and pulse motor driving for driving the pulse motor 34 Path 60, an A phase D / A converter 70 for analogly outputting the current command values to the A phase and A ′ phase of the pulse motor 34 to the drive circuit 60, and the A phase D / A conversion I / F 80 for connecting the controller 70 to the CPU 50c, and a B-phase D / A converter for converting the current command values to the B-phase and B′-phase of the pulse motor 34 into analog signals and outputting them to the drive circuit 60 71, I / F 81 for connecting the B-phase D / A converter 71 to the CPU 50c, an encoder circuit 55b for counting the count value of the encoder 55, and for connecting the encoder circuit 55b to the CPU 50c An I / F 55c, an operation panel 57 to which various settings are input, and an I / F 57c for connecting the operation panel 57 to the CPU 50c are provided.

  The control unit 50 also includes a ROM 50a in which various control programs and data used in the program are stored, data read from the ROM 50a, data input or set from the operation panel 57, and a CPU 50c described later based on the program. A RAM 50b and an EEPROM 50d that store calculated data and the like, and a CPU 50c that performs various processes based on a program are provided.

FIG. 5 is a front view of the operation panel 57. The operation panel 57 includes a pattern number display section 57a for selecting various hole shapes, an increase / decrease key 57b for selecting the pattern number, and pattern data in which set values such as dimensions are individually determined for each pattern. A display portion 57c that displays whether the item is selected, an increase / decrease key 57d that performs the selection, a display portion 57e that displays the item number of the setting item selected for the selected pattern data, and the selection of the item number of the setting item , An increase / decrease key 57f for performing the above operation, a knife adjusting key 57g for inputting a pressing amount at the time of cloth cutting driven by the pulse motor 34, and a preparation key 57h for preparing for a boring operation.
Here, the setting of the pressing amount at the time of cloth cutting driving by the knife adjusting key 57g is within a range of 10 to 100%, and for example, the ratio (%) can be set in 10 steps.
With the above function, the operation panel 57 functions as a pressing force setting means for setting a pressing force for cloth cutting (a pressing amount at the time of cloth cutting driving). Further, the pressing amount at the time of cloth cutting driving set and input by the operation panel 57 is stored in the EEPROM 50d as storage means.

  With the above configuration, when the hole shape pattern and pattern data are selected by the operation panel 57, the contents of the setting items are confirmed, and when the preparation key 57h is pressed to start sewing, first, the X axis and Y axis By the driving of the shaft motors 52a and 53a, the cloth which is the workpiece is moved to the sewing start position, and the hole sewing is started by the driving of the main shaft motor 51a. In such hole stitching, needle swinging is performed along one side of the planned formation position of the linear portion of the button hole, and when the eyelet is formed, the turning motor 54a is driven at the eyelet formation scheduled position. As a result, the stitching is performed along the periphery of the eyelet. Then, needle swing sewing is performed along the side opposite to the start of sewing of the linearly shaped portion of the button hole, and depending on the setting, tacking sewing is performed at the end portion, and the sewing is finished. Further, the fabric is conveyed to a cutting position in the cloth cutting device 30, and a button hole is formed by driving the pulse motor 34, thereby completing a series of sewing operations. The cutting operation is executed prior to sewing depending on the setting. Further, the control content of the cutting operation will be described later in more detail.

(Control configuration for cloth cutting device)
Here, the control configuration related to the cloth cutting device 30 will be described in more detail.
Note that the CPU 50c described above controls the overall operation of the eyelet sewing machine 1, but also controls the cloth cutting device 30 as a part thereof. That is, it also functions as a control unit of the cloth cutting device 30.

(Cloth cutting device: pulse motor)
First, the pulse motor 34 is a two-phase bifilar winding, and includes A-phase and B-phase coils, and A′-phase and B′-phase coils that are reversely wound.
The above-described A phase D / A converter 70 and its I / F 80 are provided for the coils of the coils A phase and A ′ phase, and the B phase D / A converter 71 and its I / F 81 are B Each of the phase and B ′ phase coils is provided.

The pulse motor 34 performs one rotation control by switching the currents of the A, A ′, B, and B ′ phases with a resolution of 400 pulses from the CPU 50c. 6 (A) to 6 (D) are diagrams showing changes in the current value energized in each coil A, A ′, B, B ′ for each pulse with respect to the rotational position of the pulse motor 34. FIG. 7 shows specific current values Ai, A′i, Bi, B′i energized in the coils A, A ′, B, B ′ for each pulse, and the CPU 50 for energizing the current values. The codes Ac and Bc (digital values) output to the A-phase D / A converter 70 and the B-phase D / A converter 71, respectively, are output for each rotation of the pulse motor 34 in (1) to (8) shown in FIG. It is the chart shown according to position. For example, when driving the pulse motor 34 with a resolution of 400 pulses, if the current is switched from (1) to (2), the pulse motor 34 rotates 0.9 degrees in the forward direction.
As shown in the figure, the change of the energization current value to each coil shows a change in one cycle in the range of -5 to +5 [A] every 8 pulses, and each coil A, A ', B , B ′ are energized such that changes in the energizing current value are delayed by 1/4 phase in order. The A ′ and B ′ phases are actually energized by inverting the positive and negative current values of the A and B phases, respectively.
When the coils A, A ′, B, and B ′ are energized, the pulse motor 34 is driven by 1-2 phase excitation (half step drive).

Next, the torque characteristic of the pulse motor 34 will be described based on the torque characteristic diagram of FIG. Here, the electrical angle τ represents one cycle (8 pulses) of the A / B phase, and the maximum torque maxT is generated when the motor rotor is delayed by 2 pulses (τ / 4) from the command value. This shows that step-out occurs after a delay of 4 pulses.
Here, the maximum torque maxT indicates the torque when the current value is periodically energized within a range of -5 to +5 [A] every 8 pulses. The torque obtained from the pulse motor 34 is determined in proportion to the amplitude of the periodic current value.

(Cloth cutting device: encoder and encoder circuit)
The encoder 55 of the pulse motor 34 is an incremental type, and 400 pulses of the A phase signal and the B phase signal are output with a 1/4 phase shift per rotation. FIG. 9 shows the A phase signal and the B phase signal of the encoder 55. As shown in the figure, the encoder circuit 55b counts by multiplying four times by counting both rising and falling edges of the pulses of the A-phase signal and the B-phase signal. Therefore, the encoder 55 can obtain a count value (resolution) that is four times the number of output pulses, and every time the pulse motor 34 is driven by one pulse, the encoder is increased (or decreased) by four counts. . Therefore, the CPU 50c can detect the rotational position of the pulse motor 34 with a resolution of 1600 counts every time the pulse motor 34 makes one revolution. Therefore, if the drive current for the pulse motor 34 is switched from (1) to (2) shown in FIG. 6, the rotation amount is detected as four pulses.
The CPU 50c can detect the position of the pulse motor 34 by reading the count value of the encoder circuit 55b.

(Cloth cutting device: D / A converter and pulse motor drive circuit)
A phase D / A converter 70 is shared by the A phase coil and A ′ phase coil, and a B phase D / A converter 71 is shared by the B phase coil and B ′ phase coil. It has been. In the following description, the A-phase coil and the A′-phase coil side will be described, but the configurations of the B-phase coil and the B′-phase coil are the same except that the energization phase is delayed by a half phase.
The CPU 50c calculates the D / A value of the excited state in which the excited state is advanced according to the current excited state (any one of the positions (1) to (8) in FIG. 7). In this cloth cutting device 30, the energization current value can be controlled in a range of 0 to 100% in accordance with a preset pressing amount at the time of cloth cutting driving, and therefore the A-phase D / A converter 70 and B The phase D / A converter 71 outputs a value obtained by multiplying the calculated D / A value by the pressing amount at the time of cloth cutting.

When the A-phase D / A converter 70 receives a code of 0 to 255 from the I / F 80, the analog signal (0, 0.02, 0.04, 0.06,... 4.98,5.00 [V]) is output to the pulse motor drive circuit 60.
On the other hand, the pulse motor drive circuit 60 energizes the coil of the pulse motor 34 with a current value obtained by dividing the range of −5 to +5 [A] into 256 levels and corresponding to an analog signal.
FIG. 10 is a chart showing the correspondence relationship between the output codes 0 to 255 of the I / F 80 and the current values that the pulse motor drive circuit 60 passes through the coils of the pulse motor 34 through the A-phase D / A converter 70. .
When the pressing amount during cloth cutting drive is 100%, the A-phase coil has +5.00, +3.54,0, -3.54, -5.00, -3.54,0, + as shown in FIG. Since it is necessary to energize the current value of 3.54 in order, the corresponding code is output in order from the CPU 50c, and when the pressing amount at the time of cloth cutting driving is set to a value other than 100%, the setting ratio is changed. A code corresponding to the multiplied value is output from the CPU 50c.
As described above, the A ′ phase coil shares the I / F 80, the A phase D / A converter 70 and the pulse motor drive circuit 60 with the A phase coil. For the cord, the pulse motor drive circuit 60 is configured to pass a current having a polarity opposite to that of the A-phase coil to the A′-phase coil. The same applies to the I / F 81, the B-phase D / A converter 71, and the pulse motor drive circuit 60 in the B-phase and B′-phase coils.

  The pulse motor drive circuit 60 includes a switching element (transistor, FET, etc.) that cuts off current to each of the A phase coil and the A ′ phase coil, a detection circuit that detects a voltage proportional to the current value of each coil, An amplifier that compares the detected voltage of each coil with an analog signal from the A-phase D / A converter 70, and a PWM output circuit that increases or decreases the on / off control ratio of energization by the switching element according to the output of the amplifier. . As a result, the switching element performs energization interruption at an on / off ratio corresponding to the analog signal from the A-phase D / A converter 70, and energization of each coil is performed at a scheduled effective current value. . The same applies to the B-phase D / A converter 71 in the B-phase and B′-phase coils.

(Cloth cutting device: cloth cutting control by CPU)
In accordance with the cloth cutting control program stored in the ROM 50a, the CPU 50c matches the knife tip of the knife 32 with the knife receiver 31 when the knife receiver 31 is moving from the standby position during cloth cutting toward the knife 32. The operation of the pulse motor 34 is performed so that the knife receiver 31 is moved to a position at a high speed, and the knife receiver 31 is switched from a position before the match at a predetermined low speed slower than the high speed until then. Take control. Here, the “matching near position” is set with some margin so that the knife receiver 31 is close to the knife 32, but even if there are individual differences or attachment errors of the knife 32 and the knife receiver 31, they do not collide. It shall indicate the height measured.
The speed control of the pulse motor 34 is executed by changing the output cycle of the command pulse to the pulse motor 34. In the high-speed movement section, a numerical signal is output so that the energization current value to each coil of the pulse motor 34 becomes 100% regardless of the set value of the pressing amount during cloth cutting drive.
With the above control, the CPU 50c functions as “movement control means” (control unit) in cooperation with the A-phase D / A converter 70, the B-phase D / A converter 71, and the pulse motor drive circuit 60. Become.

Further, the CPU 50c controls the position of the pulse motor 34 so as to advance the excitation position in the low speed section from the above-mentioned near position according to the cloth cutting control program stored in the ROM 50a, and the excitation position indicated by the command pulse of the pulse motor 34. And a detection position indicated by the encoder 55 are calculated, and it is determined whether or not the deviation exceeds a predetermined 8 count as a count value of the encoder 55. That is, the CPU 50c functions as a deviation determination unit. The deviation of 8 counts in the count value of the encoder 55 corresponds to a delay of 2 pulses in the pulse motor 34, and is a deviation in which the maximum torque maxT is generated as described with reference to FIG. Further, when the CPU 50c calculates the deviation between the command pulse of the pulse motor 34 and the detection position indicated by the encoder 55, the number of pulses for driving the pulse motor 34 once and the number of pulses detected when the encoder 55 rotates once. Are 400 pulses and 1600 pulses, respectively. Therefore, in order to match the number of both pulses, the deviation is calculated using the number of pulses that is four times the number of pulses for driving the pulse motor 34 as a command value. ing.
Further, the CPU 50c controls the driving of the pulse motor 34 so as to stop the low-speed movement of the knife receiver 31 when it is determined by the above-described deviation determination that the deviation exceeds 8 counts. By this control, the CPU 50c functions as a cutting control unit.
With the above control, the CPU 50 c functions as “cutting control means” in cooperation with the A-phase D / A converter 70, the B-phase D / A converter 71 and the pulse motor driving circuit 60.

Further, the CPU 50c executes torque control for limiting the driving torque of the pulse motor 34 in accordance with the set value of the pressing amount during cloth cutting driving in the low speed section. That is, in principle, the CPU 50c calculates the deviation between the excitation position indicated by the command pulse of the pulse motor 34 and the detection position indicated by the encoder 55, determines the driving torque from the deviation based on the PID calculation, and responds to the driving torque. Control to energize each coil with a current value is performed. However, in the low speed section, a current value (current value based on the set torque) obtained by multiplying the amplitude current value in the range of -5 to +5 [A] by the set ratio of the pressing amount at the time of cloth cutting drive is obtained, and PID calculation is performed. When the current value based on the current value exceeds the current value based on the pressing amount at the time of cloth cutting driving, control is performed to energize the coil with the current value based on the pressing amount at the time of cloth cutting driving.
With the above control, the CPU 50 c functions as “current control means” in cooperation with the A-phase D / A converter 70, the B-phase D / A converter 71 and the pulse motor drive circuit 60.

FIG. 11A shows the torque of the pulse motor 34 after the knife receiver 31 reaches the pressing start position at which the pressing force for cutting can be applied to the cloth placed on the knife 32. FIG. 11 (B) is a diagram showing a deviation after the knife receiver 31 reaches the pressing position. In each figure, the horizontal axis represents time, the symbol Tc in the figure indicates the timing when the knife receiver 31 reaches the above-described pressing start position, and Ts indicates the torque value based on the set pressing amount during cloth cutting drive. .
As shown in the figure, until the knife receiver 31 reaches the pressing start position, there is almost no deviation because there is no load. For this reason, the pulse motor 34 is driven with a torque value required for driving at low speed. When the knife receiver 31 reaches the pressing start position, a load is applied to the pulse motor 34 and the rotation speed is reduced. Therefore, the rotation position delay (deviation P), time delay (I), and deviation of the command pulse are reduced. The amount of change (D) increases. Therefore, the calculated value of the PID calculation calculated by the CPU 50c increases, and the required torque obtained from the calculated value of the PID calculation increases. Thereafter, when the deviation increases to 8 counts, the pulse motor 34 outputs the maximum torque, but when the driving torque based on the PID calculation exceeds the torque based on the set pressing amount during cloth cutting driving in the process. Thus, the pulse motor is controlled so as not to output more than the torque based on the set pressing amount during cloth cutting drive. Thereby, after the cloth is cut, even when the knife receiver 31 matches the knife 32 and further presses, the current exceeding the current value based on the set pressing amount at the cloth cutting drive is not supplied to the coil, and the knife It is possible to limit the contact pressure and the pressing force when the receiver 31 and the knife 32 are matched.

(Cloth cutting control)
Control of the cloth cutting device 30 will be described.
First, as a premise for executing cloth cutting, a setting process of a pressing amount at the time of cloth cutting driving will be described based on a flowchart shown in FIG.
First, the knife adjustment setting process is started when the operator turns on the knife adjustment key 57g of the operation panel 57. First, in response to the press of the knife adjustment key 57g, the CPU 50c displays the current pressing amount during cloth cutting driving on the display unit 57c as a percentage (step S1).
Next, it is determined whether or not there is an input from the increase / decrease key 57d (step S2). When there is no input, the process proceeds to step S4. When there is an input, the current pressing amount is increased or decreased according to the input. After the numerical value after the increase / decrease is displayed on the display unit 57c (step S3), the process proceeds to step S4.
In step S4, the CPU 50c determines whether there is an input of the knife adjustment key 57g. If there is an input, the process returns to step S2, and if there is an input, the pressing amount at the time of cloth cutting driving after increase / decrease is determined and the EEPROM 50d The stored data is updated and the setting process is terminated (step S5).

Next, cloth cutting control by the cloth cutting device 30 will be described based on a flowchart shown in FIG.
When the cloth cutting process is reached in the sewing process, cloth cutting control is started. In the cloth cutting control, first, the CPU 50c performs a pulse motor at a cycle corresponding to a high speed so as to descend from the standby position (origin position) of the knife receiver 31 to a position just before the knife 32 at a predetermined high speed. The command pulse to each coil 34 is output (step S11). At this time, the CPU 50c outputs the rotation direction signal in the normal rotation, and outputs the pressing amount at 100% regardless of the set value. That is, in such a high-speed section at the start of movement, each coil of the pulse motor 50c is energized with an amplitude of −5 to +5 [A].

Next, when the knife receiver 31 reaches a matching front position that matches the blade edge of the knife 32, the CPU 50c switches the output cycle of the command pulse so that the rotation of the pulse motor 50c is slower than the previous speed (step S12). . In addition, as described above, the knife receiver 31 is moved at a high speed to a position before the mating position where the knife receiver 31 matches the blade edge of the knife 32, so that the entire section until the cloth is cut is driven at a low speed. Cycle time can be improved.
Next, the CPU 50c calculates a deviation between the command pulse and the detection signal from the encoder 55 (step S13).
Then, it is determined whether the deviation amount is 8 or more in the count values of the A and B phase signals of the encoder 55 (step S14).
If the deviation is less than 8, the CPU 50c performs a PID calculation to calculate a necessary driving torque (step S15). Further, the CPU 50c calculates a set torque calculated based on the set value of the pressing amount (a value obtained by multiplying the torque of the pulse motor 34 when energizing each coil at -5 to +5 [A] by the set value of the pressing amount). And the drive torque obtained by the PID calculation (step S16). When the drive torque exceeds the set torque, the torque of the pulse motor 34 is calculated by the PID calculation so that the torque of the pulse motor 34 does not exceed the set torque. A torque value is set so as to be a set torque instead of the obtained drive torque (step S17). Then, the CPU 50c outputs a command pulse of the pulse motor 34 and a numerical signal indicating the pressing amount at the time of driving so that the pulse motor 34 is driven with the set torque, whereby the A-phase D / A converter 70 and The B-phase D / A converter 71 outputs an analog signal having a limited set torque value, and the pulse motor driving circuit 60 energizes each coil of the pulse motor 34 with the limited current value according to the set torque (step). S18).
On the other hand, when the drive torque is equal to or less than the set torque in step S16, the command pulse is output while the numerical signal indicating the pressing amount during torque driving remains 100%, and the pulse motor drive circuit 60 is 100% according to the drive torque. Is supplied to each coil of the pulse motor 34 (step S18).
And CPU50c waits for progress of 1 [ms], and repeats the process from step S13. That is, the CPU 50c repeatedly executes the processes of steps S13 to S19 with a period of 1 [ms].

On the other hand, in the process of step S14, when the deviation between the command pulse and the detection signal from the encoder 55 becomes 8, the knife receiver 31 has reached the knife 32 and cannot be lowered any further. The energization of each coil is maintained for 50 [ms] while maintaining the excitation position of the pulse motor 34 (step S20). As a result, the pressing force of the cloth cutting, that is, the pressing force with the set pressing amount of the knife receiver 31 against the knife 32 can be maintained for 50 [ms], and the cloth can be cut with time.
Thereafter, the CPU 50c outputs a command pulse so as to have the same high speed as that at the start of cloth cutting, outputs a rotation direction signal by reverse rotation, and outputs a pressing amount of 100%. As a result, the knife receiver 31 rises to the standby position at high speed (step S21).

(Effect of Embodiment of Invention)
In the cloth cutting device 30 according to the present embodiment, the CPU 50c functions as a deviation determination unit and a cutting control unit, monitors the deviation between the detected value of the encoder 55 and the motor command value, and the deviation amount reaches 8 counts. Since the pressing movement of the knife receiver 31 is stopped, it is possible to perform cloth cutting with a constant pressing force based on the deviation, and without the need for complicated setting work that requires skill to determine an appropriate knife adjustment value. An appropriate pressing force can be obtained. Further, in this control, movement control is performed mainly based on a deviation caused by matching of the knife 32 and the knife receiver 31, so even if the individual knife receiver 31 has variations such as size and wear amount, The pressing force can be kept constant.
Further, since the CPU 50c functions as a current control means to reduce the current value supplied to the pulse motor 34 in the low speed section, the output torque of the pulse motor 34 is also reduced, and the contact pressure when the knife and the knife receiver are matched is reduced. It is possible to alleviate and prevent mutual damage and avoid the motor step-out.
Further, since the limit value of the current value of the pulse motor 34 is determined by the operation panel 57 in accordance with the set value of the pressing force for cloth cutting, the torque of the pulse motor 34 can be arbitrarily set, and a knife or a knife receiver can be set. Therefore, it is possible to set the pressing force in detail, and it is possible to obtain a more appropriate pressing force.

(Other)
In the cloth cutting device 30, a two-phase pulse motor is used as the pulse motor 34, but a five-phase pulse motor, a three-phase pulse motor, or the like may be used. The driving method is half-step driving, but full-step driving or micro-step driving may be used.
Further, although the encoder 55 is used as the rotation amount detection unit of the pulse motor 34, a resolver, a tachometer, or the like that can detect the rotation amount may be used.
Furthermore, the resolution of the encoder 55 is not limited to 400 divisions.
The outputs of the A-phase D / A converter 70 and the B-phase D / A converter 71 are not limited to 256 gradations.
Furthermore, although the setting of the pressing amount from the operation panel 57 is the ratio (%) with respect to the maximum pressing force, it may be changed for convenience, for example, by directly setting the current value or the torque value.
In the cloth cutting device 30, the knife receiver 31 moves up and down, but the knife 32 may move up and down.
In the embodiment of the invention described above, the knife receiver 31 is lowered at a high speed until the blade tip of the knife 32 matches the knife receiver 31 and then lowered at a low speed to drive the entire section at a low speed. Although the cycle time is improved as compared with the above, it is a matter of course that the entire section may be driven at a low speed.
In the embodiment of the present invention, the case where the cloth cutting device 30 is applied to the eyelet hole sewing machine 1 is exemplified. However, the sewing machine can be used for cutting the sewing product by pressing the knife and the knife receiver against each other. The type and type of the are not limited to the eyelet drilling machine.

It is a side view which shows schematic structure of the sewing machine which concerns on this embodiment. It is a perspective view showing a schematic structure of a cloth cutting device concerning this embodiment. FIG. 3 is a top view showing a knife and a knife receiver provided in the cloth cutting device of FIG. 2, FIG. 3 (a) is an S size knife receiver, FIG. 3 (b) is an M size knife receiver, and FIG. An L size female receptacle is shown. It is a block diagram which shows the main control structure of the sewing machine of FIG. It is a front view of an operation panel. 6 (A) to 6 (D) are graphs showing changes in the value of the current supplied to each coil A, A ', B, B' for each pulse. It is the chart which showed the concrete electric current value with which each coil A, A ', B, B' is supplied with every pulse of a pulse motor. It is a diagram which shows the torque characteristic of a pulse motor. It is a diagram which shows the A phase signal and B phase signal of an encoder. 6 is a chart showing a correspondence relationship between current values of currents that are supplied to a coil of a pulse motor by a pulse motor driving circuit through a D / A converter with respect to output codes of 0 to 255. FIG. 11A shows the torque change of the pulse motor after the knife receiver reaches the knife, and FIG. 11B is a diagram showing the deviation after the knife receiver reaches the knife. It is a flowchart which shows the setting process of the pressing amount at the time of a drive. It is a flowchart which shows the cloth cutting control by a cloth cutting device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Eyelet hole sewing machine 30 Cloth cutting device 31 Knife receptacle 32 Knife 34 Pulse motor 35 Movement mechanism 50 Control part 50c CPU (movement control means, cutting | disconnection control means, current control means)
50d EEPROM (storage means)
55 Encoder (Rotation amount detector)
57 Operation panel (pressing force setting means)
60 Pulse Motor Drive Circuit 70 A Phase D / A Converter 71 B Phase D / A Converter

Claims (3)

A knife having a cutting edge;
A knife receiver that presses and cuts the cloth so as to be sandwiched in cooperation with the knife;
A moving mechanism for moving one of the knife and the knife receiver toward and away from the other;
A pulse motor serving as a drive source for the moving movement of the knife or the knife receiver by the moving mechanism;
When one of the knife or the knife receiver is moving toward the other, the knife edge of the knife moves one of the knife or the knife receiver at a predetermined low speed from a position in front of the match where the knife edge of the knife matches the knife receiver. In a cloth cutting device for an eyelet sewing machine comprising a control unit for controlling the pulse motor so as to cut the cloth,
A rotation amount detection unit for detecting the rotation amount of the pulse motor;
The controller is
Current control means for limiting a current value to be supplied to the pulse motor to be lower than that during the high speed movement during the low speed movement;
Deviation determination means for determining whether a deviation between a value detected by the rotation amount detection unit and a command value to the pulse motor is equal to or greater than a predetermined set value during the low-speed movement;
A cutting control means for controlling the pulse motor so as to stop the movement of the knife or the knife receiver when the deviation is judged to be equal to or larger than the set value by the deviation judging means;
A cloth cutting device for an eyelet-punching sewing machine characterized by comprising: A pressing force setting means for setting the pressing force of the cloth cutting;
Storage means for storing the set pressing force,
The cloth cutting device for an eyelet sewing machine according to claim 1, wherein the current control means determines a limit value of the current value according to the set pressing force.   3. The eyelet punching according to claim 1, wherein the control unit controls energization to the pulse motor so as to maintain a pressing force of cloth cutting for a predetermined time after stopping by the cutting control unit. Sewing machine.

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