JPH0616623Y2 - Sewing machine drive - Google Patents

Description

TECHNICAL FIELD The present invention mainly relates to a sewing machine drive device for driving an industrial sewing machine.

2. Description of the Related Art In recent years, in industrial sewing machine drive devices, AC servomotors are mainly used to make servomotors rapidly progressing.

An example of a conventional sewing machine drive device will be described below with reference to the drawings.

FIG. 4 shows a conventional example. In FIG. 4, 1 is an AC servo motor or a DC servo motor,
The sewing machine 6 is driven via the belt. Reference numeral 2 denotes a servo drive circuit, which includes a control circuit for driving the servo motor 1, a power supply, and the like. Reference numeral 3 denotes a drive main circuit of the servo motor 1, which drives the servo motor 1 with an AC power supply of 100 V or 200 V as an input. Reference numeral 4 denotes a transformer, which inputs an AC power source and generates an output voltage (generally, 6V and 20W are common) for lighting an illumination lamp. Reference numeral 5 is an illumination lamp for illuminating the operator's hand. A sewing machine 6 is driven by the servomotor 1 via a belt.

The operation of the sewing machine driving device configured as described above will be described below.

First, the servo motor 1 is normally stopped, and the servo drive circuit 2 operates by a drive signal from the outside,
The servo motor 1 repeats starting and stopping. Lighting lamp 5
Is normally lit to illuminate the area near the needle of the sewing machine. Since the lamps 5 have the same rating, the specifications of the transformer 4 are changed to make the output voltage constant when the specifications of the input voltage are different.

Problems to be Solved by the Invention However, in the configuration of the conventional example, the servo motor 1
Due to the large starting current, the flicker may occur in the illumination lamp 5 connected to the same system due to the instantaneous voltage drop of the power supply. In particular, when the operator's hand is illuminated by the method like the conventional example having the power supply transformer 4 for the illumination lamp inside the servo drive circuit 2, the influence of flicker is great and the operator is only uncomfortable. However, there is a problem in that the work efficiency may be lowered. On the contrary,
Although the flicker can be reduced by limiting the starting current to a small value, another problem that the rise time at the time of starting becomes long occurs. There is also a problem in that there are many types of transformer specifications depending on the input voltage.

In view of the above problems, the present invention provides a sewing machine drive device that reduces the influence of flicker of a lighting lamp at the time of starting a sewing machine drive servomotor and that does not require a change of a lamp power transformer when changing an input voltage. is there.

Means for Solving the Problems In order to solve the above problems, the sewing machine drive device of the present invention uses a DC voltage smoothed by a servo drive circuit as an input instead of the conventional power transformer for an illumination lamp, and inputs this input. It is provided with a DC / DC converter for converting into a constant lamp voltage.

The present invention has the above-mentioned configuration, and even if the power supply voltage fluctuates due to the starting current of the servo motor, the lamp voltage is kept constant, so that the flicker of the hand lighting lamp is eliminated.

Furthermore, although the specifications of the transformer have been conventionally changed according to the input voltage, one type of DC / DC converter can be used.

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

FIG. 1 shows the construction of a sewing machine driving device of the present invention. In FIG. 1, 1 is a servo motor and 2 is a servo drive circuit. Reference numeral 7 is a smoothing circuit for the main power supply of the servo drive circuit 2, which rectifies the AC input voltage and converts it into a smoothed DC voltage. Reference numeral 8 is a DC / DC converter which receives the voltage of the smoothing circuit 7 as an input and converts it into a lighting lamp lighting voltage. 5 is an illumination lamp. A sewing machine 6 is driven by the servomotor 1.

FIG. 2 shows a part of the servo drive circuit of FIG. 1 in more detail. The same numbers as in FIG. 1 indicate the same parts. A smoothing circuit 7 is composed of a diode bridge and a smoothing capacitor. Reference numeral 9 is a drive circuit for the servomotor 1. Reference numeral 8 denotes a DC / DC converter, an example of the circuit configuration of which is shown in FIG.

The operation of the sewing machine driving device configured as described above will be described below with reference to FIGS. 1 to 3.

First, in FIG. 1, it is the same as in the prior art that the power supply voltage causes an instantaneous voltage drop due to the starting current of the servo motor 1. Similarly, the output voltage of the smoothing circuit 7 also has an instantaneous voltage drop due to the starting current, but the DC / DC converter 8
Has an output voltage characteristic with respect to the input voltage as shown in FIG. 3 (b). Even if an input voltage drop occurs, the lamp lighting voltage of the output is kept constant.

Since the output voltage can be made constant with respect to such a large input voltage fluctuation, the output voltage of the DC / DC converter 8 is changed even if the rated voltage of the AC power supply changes, for example, from 100V to 115V and 200V to 240V. Is constant, and one type of the same lamp can satisfy the purpose of use.

As described above, according to the present embodiment, the instantaneous voltage drop of the power source due to the starting current of the servo motor 1 is caused by the DC / D converter 8
It becomes constant due to the constant voltage characteristic of, and the flicker of the illumination lamp 5 connected to the output can be eliminated. Also, even if the rated voltage of the power supply itself changes, the lamp voltage does not change, so there is no need to change the specifications of the transformer according to the specifications of the power supply voltage as in the past, and one type of DC
There is an advantage that the / DC converter 8 can cope.

In the embodiment of FIGS. 1 and 2, the DC / DC converter 8 receives the smoothed DC voltage of the servo drive circuit 2 as an input, but this is because the circuit configuration is rational and smoothed separately. A circuit may be provided and used.

As described above, according to the present invention, by using a DC / DC converter having a constant voltage characteristic as a power source for an illumination lamp of a sewing machine drive device, an illumination flicker of a lamp at hand due to a starting current of a servo motor is eliminated. Therefore, the discomfort of the operator can be eliminated, and the work efficiency can be improved.

Furthermore, even if the rated voltage of the power supply changes, one type of DC / DC
A converter can be used to facilitate product management.

[Brief description of drawings]

FIG. 1 is a block diagram of a sewing machine driving device in an embodiment of the present invention, FIG. 2 is a partial circuit diagram of FIG. 1, and FIG. 3 is DC / DC.
The figure which shows an example of a structure and output voltage characteristic of a converter, 4th
FIG. 1 is a block diagram of a conventional sewing machine drive device. 1 ... Servo motor, 2 ... Servo drive circuit, 5 ...
… Illumination lamp, 6 …… Sewing machine, 7 …… Smoothing circuit, 8 ……
DC / DC converter.

Claims (1)

[Scope of utility model registration request] 1. A servo motor, a servo drive circuit for driving the servo motor using an AC power supply as an input source, and a smooth DC voltage of the servo drive circuit which is operated as an input and has a constant voltage output for lighting an illumination lamp. DC / DC
A sewing machine drive device including a converter.