JPH0716553B2 - Sewing machine controller - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called belt drive type sewing machine control device for connecting a motor and a sewing machine with a belt and transmitting the rotational force of the motor to the sewing machine. is there.

2. Description of the Related Art The conventional belt drive type sewing machine drive system described above will be described below with reference to FIG.

In FIG. 7, 1 is a sewing machine, which is connected to a motor 2 via a sewing machine pulley 3, a belt 4, and a motor pulley 5. 6 is a control device, 7 is a pedal, and 8 is a needle position detector for detecting the needle position.

The operation of the sewing machine drive system configured as described above will be described below.

First, when the pedal 7 is stepped on, the control device 6 detects the stepped position of the pedal 7 by the built-in pedal sensor circuit, starts the motor 2 when the pedal 7 reaches a certain stepped position or more, and further moves to the stepped position. According to the speed setting, the speed is controlled so that the deviation from the actual speed from the speed detector built in the motor 2 becomes small.

The rotational force of the motor 2 is transmitted to the sewing machine 1 via the motor pulley 5, the belt 4 and the sewing machine pulley 3, the sewing machine is activated, and the sewing machine 1 is operated at a speed according to the depressed position of the pedal 7.

Next, the pedal 7 is moved to its original position (hereinafter referred to as the neutral position).
Then, the control device 6 stops the sewing machine 1 at a predetermined needle position detected by the needle position detector 8 (a needle down position up to the needle up position).

Problems to be Solved by the Invention As described above, the conventional one controls the speed of the motor 2 in accordance with the operation of the pedal 7, and as a result, the ratio of the sizes of the sewing machine pulley 3 and the motor pulley 5 is naturally increased. Therefore, the speed of the sewing machine 1 changes even if the speed setting by the pedal 7 is constant. Therefore, usually, the desired sewing machine speed may not be obtained because of the work of selecting and determining the motor pulley diameter from the desired sewing machine speed after measuring the sewing machine pulley diameter, or due to the difficulty in obtaining the determined motor pulley. Had problems such as.

In view of the above problems, the present invention provides a sewing machine control device in which the relationship between the pedaling position and the sewing machine speed is constant regardless of the ratio between the motor pulley and the sewing machine pulley.

Means for Solving the Problems In order to solve the above problems, a sewing machine control device of the present invention includes a counter for counting speed detection signals from the speed detector between generation signals of the needle position signal, and the pedal. Comprising a correction means for outputting a speed setting value by multiplying a speed command signal corresponding to the stepped-in position with a settable multiplier value, and a speed control means for controlling the speed according to the speed setting value.

According to the present invention, with the above-mentioned configuration, the calculating means constituting the correcting means calculates the pulley ratio between the sewing machine pulley diameter and the motor pulley diameter based on the counting result of the counter, and further, the pulley ratio is used as the multiplier value together with the calculating means. The speed command signal is set as a command to the sewing machine speed, and the speed control means controls the motor speed to the motor speed according to the speed set value. Even in this case, the sewing machine has an effect of automatically making the sewing machine speed constant with respect to the speed command signal.

Embodiment A sewing machine control device according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a block diagram of a sewing machine controller as one embodiment of the present invention. In FIG. 1, reference numeral 9 denotes a speed setting device, which detects the pedal depression amount and outputs the sewing machine start command signal S _D and the sewing machine speed command signal P _S as digital values. 10 is a multiplier, 11 is a speed control circuit, 12 is a motor, 13 is a speed detector that detects the speed of the shaft of the motor 12 and outputs a pulsed speed detection signal P _E , and 14 is the motor 12 and the belt. Sewing machine, which is connected via
Reference numeral 15 is a needle position detector which is connected to the shaft of the sewing machine 14 and detects a needle position (needle up position or needle down position) and outputs a needle position signal N _D , 16 is a counter, and 17 is a latch circuit composed of a D flip-flop. , 18 are arithmetic circuits, respectively.

Further, FIG. 2 shows a concrete configuration example of the arithmetic circuit 18. In FIG. 2, reference numeral 19 denotes a central processing unit (hereinafter referred to as “cpu”), which is synchronized with the clock signal from the oscillation circuit 20 and is input from the input port 21, output from the output port 22, input / output to the RAM 23, R _This is the part that reads instructions from _O M24. Reference numeral 25 indicates a reset circuit, which automatically switches from “L” to “H” after the operating voltage for operating the above circuits stabilizes after the power is turned on. From this point, the processing of the cpu19 is performed. Is about to start.

The operation of the sewing machine controller configured as described above will be described below with reference to FIGS. 3 and 4, particularly in the portion of FIG.

First, in FIG. 1, when the pedal is depressed for a certain amount or more, a start command signal S _D is output from the speed setter 9, the speed control circuit 11 starts the motor 12, and therefore the sewing machine 14 connected by the belt is also simultaneously started. to start. On the other hand, the speed setter 9
Outputs a speed command signal P _S according to the pedal depression position, and the multiplier 10 multiplies the set value D _P from the arithmetic circuit 18 to give a speed set value P _M to the speed control circuit 11, The control circuit 11 performs a feedback control operation such that the speed detection signal P _E from the speed detector 13 for detecting the speed of the motor 12 becomes equal to the speed set value P _M, and accordingly the motor
The speed of 12 is controlled so that the rotation speed is instructed by the speed set value P _M.

Next, when the pedal is returned to the neutral position, the speed setter 9 turns off the start command signal S _D , and the speed control circuit 11 first sets a speed sufficiently low for needle positioning according to the speed command signal P _S. Then, the speed detection signal P _E is measured, and when the actual speed reaches the positioning speed and the needle position signal N _D is further output, the motor 12 is stopped and the sewing machine 14 is moved to a predetermined needle position. To stop.

As described above, the variable speed operation by depressing the pedal and the fixed position stop control of the needle by the pedal neutrality are repeatedly performed, and the sewing is performed.Here, the set value D _P which is the gist of the present invention will be described below. Describe.

It should be noted that the counter 16 operates to count the speed detection signal P _E after the needle position signal N _D is reset at the rear edge of switching from “H” to “L”, and the latch circuit 17 causes the counter 16 to count. The output data D _C of No. 1 is latched at the time when the needle position signal N _{D changes} from “H” to “L”, and is output to the arithmetic circuit 18.

In FIG. 2, first, when the power is turned on and the reset signal from the reset circuit 25 switches from “L” to “H”, the cpu19 starts operating and fetches the instruction word from R _O M24. Start execution.

In FIG. 3, the setting value D _P1 is first set in the initial state immediately after the reset signal is switched from “L” to “H”. Next, the pedal is depressed and the start command signal S _D is “L”.
→ Enable the interrupt from the time of switching to “H”, and at the second switching point of the needle position signal N _{D from} “H” to “L”, that is, when the sewing machine 14 makes one rotation, The data D _E of the latch circuit 17, that is, the number of pulses of the speed detection signal P _E indicating the rotation angle of the motor 12 during one rotation of the sewing machine 14 is input and substituted into the following equation (1) for calculation.

D _P = D _E ÷ R (1) (where R is the number of pulses of the motor rotation speed detection signal P _E ) That is, the result D _P in equation (1) is the rotation angle ratio of the motor shaft to the sewing machine shaft, that is, The ratio between the sewing machine pulley diameter and the motor pulley diameter (hereinafter referred to as the pulley ratio) is shown. Therefore, if the speed command value of the sewing machine is N _SM and the speed command value of the motor is N _MT , formula (2) is established.

N _MT = N _SM × D _P (2) The motor speed command value N _MT in the equation (2) corresponds to the speed set value P _M in FIG. 2, and therefore the speed command signal P _S
Can be said to indicate the speed command value of the sewing machine. Therefore,
It can be said that the above shows a correction means for obtaining a constant sewing machine speed for any pulley ratio.

Here, the above-mentioned pulley ratio D _P1 at the time of initial setting cannot be measured immediately after the power is turned on, so an appropriate value is set, but the low speed during needle positioning as described above (when the pedal is neutral) Is also given as the speed setting signal P _S ), and if it becomes too high, there is a problem that the slip angle of the needle stop position becomes large and the stopping accuracy deteriorates. A small value such as 3/1 to 4/1 is selected.

Further, the portion shown by the broken line in FIG. 3 (b) shows the processing in the case of an abnormality. That is, 26 indicates that when the pseudo needle position signal N _D is continuously input from “H” to “L” due to noise or the like, the latch output D _E becomes a very small value. Reference numeral 27 denotes a prohibition means that does not perform the calculation, and does not perform the calculation when the latch output D _E becomes a very large value due to noise added to the speed detection signal P _E.

FIG. 4 details the method of setting the set value D _P until the calculation of the pulley ratio is completed, and will be described below with reference to FIG. Normally, by the timer built in the cpu19,
Interrupt processing is performed every fixed period t ₁ . In FIG. 3, when the start command signal S _D is output, the timer process becomes effective, and the timer interrupt process is performed along with the interrupt process (“H” → “L”) by the pulse signal of the speed detection signal P _E. The period of the speed detection signal P _E is measured by and the period is t ₁ × T
Just value [Delta] D _P to the pulley ratio D _P if it exceeds _M1
The control such as adding is repeated. That is, the control of the motor 12 generally has a characteristic that the speed decreases as the load torque increases, and it is possible that the motor cannot be started if the speed is set too low. Means for increasing the value D _P are effective. It should be noted that the above-mentioned T _M1 may be set to a value corresponding to a speed low enough to determine whether or not the motor 12 has started.

Examples of the time charts for the above-described operations of FIGS. 3 and 4 are shown in FIGS. 5 and 6, respectively, and further description will be given according to the same drawings.

As shown in FIG. 5, until the needle position signal N _{D, which} is generated once for each rotation of the sewing machine 14, passes twice,
A sufficiently small value D _P1 is set as D _P , and the motor speed starts operation at a low speed, but after calculating the pulley ratio as described above, it switches to the normal speed setting, and the calculation result value D _The motor speed based on _P2 will be obtained.

Next, as shown in FIG. 6, when the motor 12 cannot be started immediately after the start command signal S _D is output and the sewing machine load is large, the setting is made by ΔD _{P for} each time t _1. Raise the value, start at t _s , and then operate as described above.

As described above, according to the present invention, by providing the arithmetic circuit 18 and the multiplier 10, the ratio between the diameter of the sewing machine pulley and the diameter of the motor pulley is measured, and the multiplier 10 outputs the speed command signal P _S to the Since the speed setting value P _M of the motor 12 is output by multiplying the measured pulley ratio, the speed command signal P _S commands the sewing machine speed. In other words, in other words, according to the present invention, the diameter of the sewing machine pulley and the diameter of the motor pulley are measured and automatically corrected, so that the sewing machine speed as set can be obtained at any pulley ratio.

The needle position signal N _D described above is generated once for each rotation, but it should be understood that a plurality of needle position signals N _D can be arranged per rotation and the object of the present invention can be achieved even if they are arranged at equal angular intervals. Becomes That is, if it is assumed that the number of the detection signals is M, it can be said that the following equation (3) may be used as an arithmetic expression. (Instead of expression (1)) EFFECTS OF THE INVENTION As described above, the present invention includes a counter that counts speed detection signals between generation signals of needle position signals, and a correction unit that corrects a speed command signal according to the count result of the counter and outputs a speed setting value. Since the ratio between the diameter of the sewing machine pulley and the diameter of the motor pulley is actually measured and automatically corrected, the sewing machine speed as set can be obtained for any pulley ratio. Will be things.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a sewing machine controller according to an embodiment of the present invention, FIG. 2 is a block diagram of an arithmetic circuit in the same, and FIGS. 3 and 4 show arithmetic operations. FIG. 5 is a flow chart showing the operation, FIG. 5 and FIG. 6 are time charts showing the operation,
FIG. 7 is a front view of a sewing machine showing a configuration of a conventional example. 9 ... Speed setter, 10 ... Multiplier, 11 ... Speed control circuit, 12 ... Motor, 13 ... Speed detector, 14 ... Sewing machine,
15: Needle position detector, 16: Counter, 18: Arithmetic circuit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Doi 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP 61-257688 (JP, A) JP 61-257687 (JP, A) JP-A-61-257689 (JP, A)

Claims (1)

[Claims] 1. A speed setter for generating a speed command signal, a motor, speed detecting means for generating R speed detection signals per rotation to detect the speed of the motor, a speed set value and the speed. Speed control means for controlling the speed of the motor by the detection signal, a sewing machine coupled with the motor via a belt mechanism, a needle position detector for detecting a needle position of the sewing machine and generating a needle position signal, A counter that counts the speed detection signal and outputs a count value C between the generation signals of the needle position signal, a calculation means that performs calculation C / R, and the speed command signal multiplied by the calculation result to output a speed set value. A sewing machine control device comprising: a correction unit including a multiplier.