JPS62395A - Sewing machine speed control device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a sewing machine that performs sewing using rotational force obtained through a pulley, a motor that serves as a driving source for the sewing machine, and a speed control circuit that controls the motor. The present invention relates to a sewing machine speed control device equipped with a sewing machine speed control device.

BACKGROUND OF THE INVENTION A conventional sewing machine speed control device will be described below with reference to FIG.

In Fig. 5, 1 is a sewing machine, 2 is a sewing machine stand, 3 is a pedal, 4 is a motor for driving the sewing machine 1, 5 is a needle position detector, 6 is a braking device, and the sewing machine 1 has a sewing machine pulley 7 and a motor pulley. Rotational force is obtained from the motor 2 by connecting the motors 8 with a belt.

Regarding the sewing machine speed control device configured as above,
The operation will be explained below.

The pedal 3 can be depressed forward or backward, and a signal corresponding to the amount of depression is set in the control device 6 as a sewing machine target speed signal. On the other hand, the control device 6 actually measures the actual speed of the sewing machine using a built-in speed detector, compares it with the sewing machine target speed signal, and controls the motor so that the deviation is minimized.

When actually measuring and comparing sewing machine speeds as mentioned above, the ratio of the diameter of sewing machine pulley 7 to motor pulley 8 (hereinafter referred to as
Accurate speed control is impossible unless a suitable motor pulley 8 is selected so that the pulley ratio (referred to as the "boot ratio") is constant, that is, the number of rotations relative to the rotation of the sewing machine is a predetermined value. So we actually measured the motor speed,
A sewing machine speed control device has been proposed that solves the above problem by comparing the result with a signal obtained by converting the sewing machine target speed signal into a motor speed (hereinafter referred to as a motor target speed signal). The content is that by adding a speed detector to the motor side that outputs R signals per motor rotation, it is possible to actually measure the actual speed of the motor (hereinafter referred to as motor actual speed). , a counter that counts the number of output signals of the speed detector generated between the output signals of the needle position detector 5, and a multiplier that can set a multiplication value, so that the multiplication is performed until the counter finishes counting. The device sets A' as a multiplication value, multiplies it by the sewing machine target speed signal and outputs a provisional motor target speed signal, and when the counter finishes counting and outputs the result C', C'
/R is performed to calculate the boob ratio, that is, the number of motor rotations per one revolution of the sewing machine, and by using that value as a multiplier value, it is possible to output an accurate motor target speed signal by multiplying it by the sewing machine target speed signal. As a result, accurate speed control is possible no matter what the pulley ratio is.

Problems to be Solved by the Invention However, in the above configuration, if a value larger than the pulley ratio is measured as the multiplier value A', the low speed during needle positioning becomes faster and the stopping accuracy becomes lower. It is necessary to choose the lowest value of the possible actual booger ratios, such as 1/3 to 1/4, because there is a risk that the sewing machine may become damaged or the thread trimming speed may be too fast. there were. Therefore, when the boob ratio is large, such as in a large sewing machine, the sewing machine speed is slow when the power is turned on, so it takes time to calculate the boob ratio, and as shown in Figure 4, the sewing machine speed suddenly increases after the boop ratio is calculated. There are problems such as faster speed.

The present invention solves this problem when turning on the power, and increases the multiplier value in stages from when the power is turned on until the pulley ratio is calculated, thereby increasing the sewing machine speed and booting. This reduces the time required to calculate the ratio, and
To provide a sewing machine speed control device that can obtain smooth acceleration.

Means for Solving the Problems The sewing machine speed control device of the present invention provides an adder that performs addition in synchronization with the output signal of the speed detector and outputs the result, and an output signal that is generated between the output signal of the needle position detector. A counter that counts the output signal of the speed detector, and a multiplication value is set from either the result of the adder or the result of the counter, and the product is multiplied by the sewing machine target speed signal that is the output of the speed setting device to set the motor target. It is composed of an arithmetic unit that outputs a speed signal and an arithmetic means that determines the multiplication value.

Effect: With the above configuration, the sewing machine speed control device of the present invention can increase the multiplication value by which the sewing machine target speed signal is multiplied every n rotations of the motor from the time the power is turned on until the pulley ratio calculation. It is possible to shorten the time required to reach the target position and obtain smooth acceleration.

EXAMPLE An example of the present invention will be described below with reference to the drawings.

FIG. 1 shows a block diagram of a sewing machine speed control device in one embodiment of the present invention. In FIG. 1, 1 is a sewing machine, 3 is a pedal, and 4 is a motor for driving the sewing machine 1. 5 is a needle position detector that detects the needle position of the sewing machine 1, and receives a needle up position signal Nu and a needle down position signal Nd.
Output.

9 is a speed setting device which outputs a signal corresponding to the amount of depression of the pedal 3 as a sewing machine target speed signal. 10 is a speed detector that outputs R signals each time the motor 4 rotates once, and 11 is a frequency divider that divides the output signal of the speed detector 10 by n. 12 and 13 are latch circuits made up of flip-flops. An adder 14 performs addition in synchronization with the signal from the frequency divider 11, and adds the added value stored in the latch circuit 12 to the currently held value and outputs the result.

A counter 15 counts the output signal of the speed detector 10, and is reset by the force signal Nd from the needle position detector 5. 1
6 is an arithmetic unit which multiplies the sewing machine target speed signal output from the speed setting device 9 by a multiplication value and outputs the motor target speed.

A switch section 17 sets either the result of the adder 14 or the result of the counter 15 as data for determining the multiplication value of the arithmetic unit 16. A speed control section 18 compares the motor target speed signal output from the calculator 16 with the actual motor speed, and outputs a voltage signal to the motor 4.

Regarding the sewing machine speed control device configured as above,
Hereinafter, the operation when the power is turned on will be explained.

When the power is turned on, Ai and Ao are set as initial values in the latch circuit 12 and the adder 14, respectively. Further, Sl of the switch section 17 is in the ON state. When the pedal 3 is depressed, a sewing machine target speed signal corresponding to the amount of pedal depression is outputted from the speed setting device 9. Switch part 17-3
1 is in the ON state, the arithmetic unit 16 determines a multiplication value from the result of the adder 14 in synchronization with the signal of the built-in oscillation circuit, and uses the multiplication value as the sewing machine target speed signal which is the output of the speed setting device 9. The sewing machine target speed is converted into a motor speed by multiplying by the motor speed signal, and is output as a motor target speed signal. The speed control unit 18 compares the motor target speed signal output from the calculator 16 and the actual motor speed measured from the output signal of the speed detector 10, and applies a voltage to the motor 4 so that the deviation is minimized. Output a signal. The motor 4 is activated by the voltage signal. When the motor 4 starts, the sewing machine starts, and the speed detector 10 also detects the motor 4.
Outputs a signal according to the rotation angle. The frequency divider 11 outputs a signal to the adder 14 every time it receives n-R output signals from the speed detector 10, in other words, every time the motor 4 rotates n times. The adder 14 adds the addition value Ai stored in the latch circuit 13 to the currently held value in synchronization with the output signal from the frequency divider 11. Here, the arithmetic unit 16 newly determines a multiplication value from the result of the adder 14, and thereafter repeats the above operation until the boolean ratio is calculated.

On the other hand, the needle position detector 5 outputs a needle down position signal Pd every time it detects the needle down position. The counter 15 receives the needle down position signal P.
The output signal of the speed detector 10 is reset at the falling edge of the speed detector 10, and thereafter the output signal of the speed detector 10 is counted until the signal is reset to zero. Latch circuit 1
3 is the fall of the needle down position signal Pd, and the result C of the counter 15 is stored. When the needle down position signal Pd is inputted for the second time, the switch section 17 turns Sl into an OFF state and turns S2 into an ON state, and maintains the current state even if the needle down position signal Pd is inputted thereafter. Figure 2 shows the operation in a professional chart.

By performing the above operations, the arithmetic unit 16 performs the following calculations. The multiplication value 13 of the arithmetic unit 16 is determined by equation (1).

Multiply value: B=(Ao+AiXj)/R (before pulley ratio calculation, when Sl is ON) Multiply value: B=C/R (after pulley ratio calculation, when S2 is ON) ・
...(1) j: Number of output signals of frequency division 11: Ao: Adder 1
Initial value of 4: A: Added value, R: Number of output signals of speed detector 10 per rotation of motor 4. 20: Result of counter. A motor target speed signal is output by multiplying the target speed signal. FIG. 3 shows the relationship between time and motor target speed. As for Ao, depending on the actual pulley ratio that can be considered and the needle position when the power is turned on, the sewing machine may make two revolutions before calculating the boar ratio, so it is possible to make two revolutions before calculating the boar ratio. Therefore, it is necessary to determine Ai and n so that the result of the adder before calculating the boolean ratio/rate is thicker than the actual boolean ratio (for example, Ai = -.

n=-).

Effects of the Invention As described above, the present invention has the result that the time required to calculate the bobbin ratio can be shortened, and even a large sewing machine can be smoothly accelerated.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a flowchart showing the operation of the embodiment, FIG. 3 is a time chart showing the operation, and FIG. 4 is a diagram showing the operation of the conventional example. The time chart in FIG. 5 is a schematic configuration diagram of a conventional example. 5... Needle position detector, 9... Speed setter, 10... Speed detector, 11... Frequency divider, 14... ... Adder, 1.5 ... Counter, 16 ... Arithmetic unit. 1- Sewing machine 4- Motor 5- Needle position detector 9- Lost & projector 10--1 Distance detector n-11 Oscillator tz, tz-La Sochi circuit/4-1 Addition grave 15 --One counter 16--Arithmetic unit Figure 2 Figure 3 Box Figure 4 Steps

Claims (1)

[Claims] A sewing machine that performs sewing using rotational force as a driving source, a needle position detector that detects the needle position of the sewing machine and generates a needle position signal, a motor that serves as the driving source of the sewing machine, and a target speed signal of the sewing machine that outputs a signal. It consists of a speed setter, a speed detector that outputs R pulse-shaped actual speed signals during one rotation of the motor, and a speed control circuit that controls the rotational speed of the motor, and the speed control circuit is , an adder that sets an initial value when the power is turned on, and thereafter adds an additional value every n pulses of the speed signal and outputs the result A, and counts the actual speed signal generated between the needle position signals; A counter that outputs the result C and an A/R until the counter finishes counting.
The target speed signal is multiplied by C/R after counting is completed.
A sewing machine speed control device comprising: a computing unit that multiplies the target speed signal by the target speed signal, and comparing an output signal of the computing unit with the speed signal to control the motor.