JP2781281B2 - Sewing machine stop control method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewing machine stop control method and apparatus, and more particularly to a sewing machine stop control method and apparatus for stopping a sewing machine in response to a sewing machine stop command.

[0002]

2. Description of the Related Art Conventionally, when the sewing machine is stopped or stopped in a sewing machine driving device, the sewing machine control means detects when the pedal is released, detects a needle down signal in the needle down stop mode, and issues a stop command to the motor control means. To stop the sewing machine. Specifically, when stopping the sewing machine, by detecting the rotation speed of the sewing machine shaft or the sewing machine drive motor shaft, control is performed after a predicted time when the rotation speed will become zero from a time when the rotation speed falls below a certain specified speed. Is to be terminated.

[0003]

Particularly, in a device for driving the sewing machine head by a motor via a belt, the rotation of the motor is stopped at the time of stopping the hand, and even though the motor is once stopped, FIG. As shown in A), due to the inertia of the sewing machine shaft 50, the sewing machine shaft stops while leaving slack and tension on the sewing machine belt 52 between the sewing machine shaft 50 and the motor shaft 51.

For this reason, as shown in FIG. 8 (B), when the machine shaft stationary force F2 is smaller than the motor shaft stationary force F3, the sewing machine shaft 50 loses the belt tension and reverses. Due to this reversing force, a small amount of tension acts on the opposite side, but the inertia force F4 of the sewing machine shaft 50 causes the motor shaft 51 to also reverse. Thus belt 5
The sewing machine shaft 50 is reversed until the tension F1 of No. 2 is attenuated.

FIG. 9A shows a case where the machine shaft stationary force F2 is larger than the motor shaft stationary force F3, and the sewing machine shaft 50 is normally rotated for the same reason. On the other hand, FIG. 9 (B) shows a case where the sewing machine shaft stationary force F2 is the same as the motor shaft stationary force F3. However, since the belt tension F1 is immediately balanced, the sewing machine shaft 50 is settled in a state in which the sewing machine shaft 50 slightly vibrates in the forward and reverse directions.

If the sewing machine shaft is reversed at the needle lower position at the time of stopping the hand, as shown in FIG.
The needle 5 may come off the needle thread loop 56 formed on the needle 57. At this time, the loop shape of the upper thread tends to become narrower, and the case where the lower thread hook point does not enter the loop at the time of re-forward rotation tends to occur. As a result, a seam is not formed, and a so-called “eye skip” is formed, which causes a sewing trouble.

Further, if the sewing machine shaft rotates relatively large at the needle lower position at the time of stopping the needle, the needle tip comes off from the fabric, and the needle does not become a pivot point when the direction of the fabric is changed. In some cases, an impossible trouble may occur.
In addition, if there is a situation where the needle lower detection position is exceeded, the thread trimming operation is started only at the time of the needle lowering detection at the time of the automatic thread trimming control.

Accordingly, the present invention has been made in order to eliminate such a conventional disadvantage, and the present invention has been made to reduce the speed of the motor.
It is an object of the present invention to provide a sewing machine stop control method and apparatus capable of removing the generated slack and tension of the belt and accurately stopping the motor shaft or the sewing machine shaft in a predetermined state when the sewing machine stops.

[0009]

According to the present invention, there is provided a sewing machine stop control method for stopping a sewing machine in response to a sewing machine stop command, the method comprising: The sewing machine shaft is a motor
Give slack and tension to the belt wound around the shaft to reduce
Hayashi, and the motor is trace rotating or immediately before when the rotational speed of the sewing machine drive motor is approximately zero belt
A configuration that removes slack and tension has been adopted.

Further, according to the present invention, in a sewing machine stop control device for stopping a sewing machine at a predetermined position in response to a sewing machine stop command, a motor shaft of a sewing machine drive motor and a sewing machine shaft are provided.
A belt wound between the belt, means for detecting the rotation speed of the sewing machine driving motor, and means for instructing stop of driving of the sewing machine
When the motor rotational speed becomes almost zero or immediately before, the motor is moved in the direction to remove the slack and tension of the belt.
Provided and means for only trace amounts rotation period of the constant, the deceleration control sewing machine drive motor speed in accordance with an instruction indicating means, the rotational speed of the sewing machine drive motor detected in the detection means
When the belt becomes almost zero or immediately before it,
A configuration for controlling the rotation of the motor in a direction to remove the tension is also adopted.

[0011]

According to such a configuration, the motor is driven by the belt when the motor rotational speed becomes almost zero or immediately before .
Make a slight rotation for a predetermined period in the direction to remove slack and tension.
As a result, the sewing machine shaft is stopped at a predetermined position.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the drawings.

FIG. 1 shows the appearance of a sewing machine to which the present invention is applied. When the sewing machine pedal 1 is depressed or released, the motor. Sewing machine controller 2
The drive of the sewing machine motor 4 can be controlled via the. The driving force of the sewing machine motor 4 is transmitted to the sewing machine main shaft 5 via the belt 3, and sewing is performed through a sewing machine sewing portion 7 as is well known. Reference numeral 6 denotes a synchronizer that detects a needle up position and a needle down position in accordance with the rotation of the main shaft of the sewing machine.

FIG. The control block diagram of the sewing machine controller is shown. motor. The sewing machine controller comprises a sewing machine control means 17 and a motor control means 12, each of which has a known CPU. ROM. The circuit is configured by a RAM or the like. A pedal sensor 15 and a sewing machine needle position detector 16 are connected to the sewing machine control means 17. A setting device 18 is connected, and an output signal from the motor control means 12 is transmitted to the sewing machine motor 1 via a motor driver 13.
4 to drive the motor at a predetermined speed.

When the pedal 1 is depressed, the amount of depression is detected by a pedal sensor 15, and a rotation command and a rotation speed are instructed from a sewing machine control means 17 to a motor control means 12 in accordance with the depression amount. When a motor control command is input as shown in step S1 of the flowchart in FIG. 3, the motor control means 12 determines the command (step S2). The drive current value is output, and the sewing machine motor 14 is rotated. When the motor 14 rotates, the belt 3
The sewing machine main shaft 5 is also rotated via.

The motor speed and the motor position are detected by a motor speed detector 10 and a motor position detector 11 which are constituted by an encoder mounted on the motor shaft, and the rotation of the motor is controlled by a motor control means 12. The needle up position and the needle down position are detected by the sewing machine needle position detector 16 in the synchronizer 6 for each rotation according to the rotation of the sewing machine spindle.

On the other hand, if it is determined that the pedal has been released, the sewing machine control
It detects a needle down signal (20 in FIGS. 5 and 6) and outputs a stop command (21 in FIGS. 5 and 6) to the motor control means. At this time, upon receiving the stop command (step S3), the motor control means controls to stop the motor (step S4). If it is not a stop command, the PWM output (22 in FIGS. 5 and 6) is stopped in step S5.

In the case of the motor stop control in FIG. 3, the process proceeds to the hand stop control performed by the control as shown in FIG.
When the motor stop control T1 is reached, the motor control means 12 receives the stop command and executes step T2.
The speed is detected by the motor speed detector 10 in the following manner.
In the case of the difference, the control is performed step by step.

(1) The motor rotation speed is reduced from A to B by the stop command 21 as shown in FIGS. Step T
3, the motor rotation speed is set to a set value, for example, 50 rpm.
When it is determined that the above is the case (section between A and B), a reverse rotation output is output to the motor driver 13 and a motor drive current amount control PWM (pulse width modulation) value is calculated by multiplying a gain by using the detected motor speed as a deviation. , A value that gradually reduces the braking force is obtained and output to the motor driver 13. As a result, the motor rotation speed is rapidly reduced (step T
5).

(2) Due to this deceleration, the motor rotation speed is reduced to a low value in step T4, for example, 10 rpm to 49 rpm.
(Sections B to C in FIG. 6), the
At step 6, the motor drive current control PWM output is stopped. As a result, the motor rotation speed gradually decreases and stops.

(3) When the control is terminated here, FIG. 9 and FIG.
In the case where the phenomenon described with reference to FIG. 0 occurs and the machine shaft static force is smaller than the motor shaft static force, reverse rotation occurs as indicated by 23 in FIG.

Therefore, at step T4, an extremely low speed (for example, 1
0 rpm) (area C in FIG. 6), it is determined in step T7 whether the slack removal mode is set. If it is not set, the slack removal mode is initialized in steps T8 to T11. That is, a forward rotation is output to the motor driver, a PWM value that can be restarted is set, and the PWM output is set to an off timer so that the motor output can be stopped after a lapse of a small amount of forward rotation, and the PWM value is output to the motor driver. Set the mode and start the timer.

The off-timer value can be changed by reading the value of the forward rotation period setting unit 18 at the time of motor initialization (step S7).

When the slack removal mode is set as described above, the PWM output is stopped when the set time is reached by monitoring the PWM output off timer in step T12 (step T13).

By this means, the slack and tension generated at the time of stopping the hand are not locked on the motor shaft side, but a small amount of forward rotation is output to the motor in order to positively eliminate the belt tension, thereby absorbing the energy of the belt tension. Therefore, after the sewing machine stops, the sewing machine shaft can be stopped without being reversed.

In FIG. 4, the off-timer is set to monitor the PWM output amount of the re-rotation output of the motor to monitor the normal rotation time. However, as shown in steps T7 'to T13' in FIG. The amount of forward rotation of the motor at that time may be controlled by counting the number of pulses of the PWM output.

In the above-described example, it is assumed that the motor when the sewing machine stops is in the forward direction. However, when the sewing machine main shaft rotates excessively in the forward direction, the motor when the sewing machine stops in the reverse direction. Alternatively, the motor may be rotated for a predetermined time or a predetermined number of pulses.

As described above, it is possible to stop the needle while suppressing the forward or reverse rotation phenomenon of the main shaft of the sewing machine. Therefore, it is possible to prevent a sewing trouble such as "jump skipping" and a trouble that the needle tip comes off from the fabric when the needle stops. Prevention, troubles that cannot be automatically trimmed can be prevented. Further, when the needle stops at the needle lower position, by suppressing the reversal phenomenon of the sewing machine main spindle, the stitch tip of the sewing machine lower thread is prevented from coming off the upper thread loop, so that a normal sewing operation can be performed.

[0029]

As described above, according to the present invention,
Or in immediately before the time the motor speed is substantially zero
Set the motor in the direction to remove the slack and tension of the belt.
Since the sewing machine shaft is stopped at a predetermined position by performing a slight rotation only for a period , inconveniences such as a reverse rotation phenomenon of the sewing machine shaft when the sewing machine stops can be eliminated, and the sewing machine shaft can be reliably stopped at a predetermined position. Also, belt slack
Sewing machine shaft damping after motor stop caused by tension and tension
There is no movement and the sewing machine shaft can be stopped at a fixed position.
Time to complete stop because there is no damping movement
Can be shortened, and exercise due to slack and tension
Energy is consumed by the belt's own movement (damping movement)
The belt itself is not absorbed by the rotation of the motor.
And the life of the belt can be extended.
There is an excellent effect that it can be done .

[0030]

[Brief description of the drawings]

FIG. 1 is a perspective view showing an appearance of a sewing machine to which the present invention is applied.

FIG. 2 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 3 is a flowchart showing a flow for controlling a motor.

FIG. 4 is a flowchart showing a control flow when the motor is stopped.

FIG. 5 is a diagram showing a case where a reverse rotation phenomenon occurs when the motor stops.

FIG. 6 is a diagram showing control for eliminating a reverse rotation phenomenon when the motor is stopped.

FIG. 7 is a diagram showing an example of another control for eliminating the reverse rotation phenomenon when the motor stops.

FIG. 8 is an explanatory diagram illustrating forces acting on a motor shaft and a sewing machine main shaft.

FIG. 9 is an explanatory diagram illustrating forces acting on a motor shaft and a sewing machine main shaft.

FIG. 10 is an explanatory diagram for explaining a connection state of a lower thread and an upper thread.

[Explanation of symbols]

 Reference Signs List 10 motor speed detector 11 motor position detector 12 motor control means 13 motor driver 14 sewing machine motor 15 pedal sensor 16 sewing machine needle position detector 17 sewing machine control means

Claims (5)

(57) [Claims] 1. A sewing machine stop control method for stopping a sewing machine in response to a sewing machine stop command, wherein a sewing machine drive motor is decelerated by the sewing machine stop command, and a sewing machine shaft is provided on a belt wound around the motor shaft. Sagging
When the rotation speed of the sewing machine drive motor becomes almost zero or shortly before or shortly before the rotation speed of the sewing machine drive motor is reduced by applying tension, the belt is slackened.
A sewing machine stop control method characterized by removing tension . 2. The method according to claim 1, wherein the direction of the minute rotation is a forward direction . In the sewing machine stop control device for stopping the 3. sewing machine in response to the stop command of the sewing machine at a predetermined position, wound of between the motor shaft and the sewing axis of the sewing machine drive motor
Belt, means for detecting the rotational speed of the sewing machine drive motor, means for instructing the sewing machine to stop driving, and when the motor rotational speed becomes almost zero or immediately before that.
Set the motor in the direction to remove the slack and tension of the belt.
Means for slightly rotating for a period is provided, and the speed of the sewing machine drive motor is controlled to be reduced according to the instruction of the instruction means, and when the rotation speed of the sewing machine drive motor detected by the detection means becomes almost zero or immediately before that. bell
Rotation of the motor in the direction to remove slack and tension
Sewing machine stop control apparatus characterized by that. 4. The stop control device for a sewing machine according to claim 3, wherein said predetermined period can be set to a desired period. 5. The stop control device for a sewing machine according to claim 3, wherein the minute rotation is a forward rotation.