JP2001197673A - Device using lithium battery, and injection molding machine using device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device, using a lithium battery provided with a unit that is less prone to voltage drop and malfunctions due to voltage drop, even if the lithium battery out of operation for an extended period of time is used as an operation power supply. SOLUTION: The device contains a dummy load 14 of a prescribed resistance value that can be connected to a lithium battery 3, a timer 15 that counts the time of the operation of an encoder 1 using a power supply unit 2 utilizing commercial alternating-current power, and a control switch 16, where when the count on the timer 15 reaches a prescribed time of operation, the dummy load 14 is connected to the lithium battery 3 to discharge the battery only for a prescribed discharging time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding machine for detecting the position of a component using an encoder and performing various operation controls based on the detection result, for signal generation and / or data storage. The present invention relates to an apparatus having a unit for performing the operation, and using a lithium battery as a power supply backup unit of the unit.

[0002]

2. Description of the Related Art There is an injection molding machine as an apparatus having a multi-rotation type semi-absolute encoder (hereinafter simply referred to as an encoder). In order for the encoder to operate (generate an encode signal and / or temporarily store encoded data), power supply is required. For example, a DC power supply with a voltage of 5 V is connected to the encoder. Specifically, a DC power supply device that converts commercial AC power into DC power with a voltage of 5 V and outputs the DC power is usually connected to the encoder. However, the encoder is also provided with an emergency power supply using a lithium battery in preparation for an unexpected situation in the event of a commercial AC power failure or when the voltage of the control power supply (DC power supply) drops or is turned off.

FIG. 2 is a schematic diagram showing only an encoder portion of this type of injection molding machine. Referring to FIG. 2, power supply device 2 having a voltage of 5 V is normally connected to encoder 1. The encoder 1 itself has a function of monitoring the output voltage of the power supply device 2 and a function of switching the operation power supply based on the monitoring result. For example, the power supply device 2 is normally operated by the power supply device 2. However, when the output voltage of the power supply device 2 falls to a predetermined value or less due to a power failure of commercial AC power or the like, the encoder 1 supplies power to the lithium battery 3 from the power supply device 2. Switch to continue operation. At this time, the encoder 1 continues to monitor the output voltage of the power supply device 2. Therefore, when the output voltage of the power supply device 2 is restored until the output voltage exceeds the predetermined value, the operation power supply is switched from the lithium battery 3 to the power supply device 2 again.

That is, the lithium battery 3 is not used unless the output voltage of the power supply device 2 drops below a predetermined value due to a power failure of commercial AC power or the like.

[0005]

Generally, in a lithium battery, a passivation film is formed on the surface of an electrode in a non-use state, and this passivation film suppresses spontaneous discharge and is used for a long period of time. On the other hand, when a load is connected, the passivation film acts as an internal resistor R as shown in the conceptual circuit diagram of FIG. 3, so that the voltage temporarily drops (from the no-load voltage to the transient minimum). Voltage). The passivation film on the electrode surface is
It grows in large quantities when the unused time is long, and at high speed when the environmental temperature is high.

The effect of increasing the internal resistance of a lithium battery due to the formation of a passivation film becomes more pronounced as the value of the current flowing through the lithium battery increases. In other words, there is almost no problematic voltage drop when the energizing current value of the lithium battery is on the order of microampere, but when the current is several milliamperes or more, the above-mentioned voltage drop becomes remarkable.

[0007] Encoders typically operate due to their operation.
Since it is necessary to supply a current of several milliamps to several hundreds of milliamps or more, a voltage drop phenomenon occurs when a lithium battery after a non-use state is used as an operation power supply. When a voltage drop occurs, the minimum operating voltage of the encoder cannot be ensured, so that a malfunction such as a malfunction of the encoder may occur.

In particular, as described above, a lithium battery used as an emergency power source in an injection molding machine may be used as long as the voltage of a DC power source does not drop below a predetermined value due to a power outage of commercial AC power or the like. Basically, the non-use time is quite long because there is no. Since this lithium battery is also used for an encoder provided in an injection molding machine, its environmental temperature is considerably high. In other words, the lithium battery used as the emergency power source for the encoder of the injection molding machine satisfies the condition that the passivation film is most likely to grow.

The problem described above is not limited to the injection molding machine having the encoder described above, and a DC power supply using commercial AC power is normally used as an operating power supply, while a lithium power supply is used when the power supply voltage of the DC power supply drops. The same can be said for all devices having a unit for generating a signal and / or storing data using a battery.

[0010] Therefore, an object of the present invention is to provide an apparatus having a unit which is less likely to cause a voltage drop and a malfunction due to the voltage drop even when a lithium battery which is not used for a long time is used as an operation power supply. It is to provide.

Another technical object of the present invention is to provide an injection molding apparatus having an encoder which is unlikely to cause a voltage drop and a malfunction due to a voltage drop even when a lithium battery which is not used for a long time is used as an operation power supply. Is to provide a machine.

[0012]

According to the present invention, there is provided an apparatus having a unit for generating a signal and / or storing data using an operation power supply, wherein the unit is normally used as a commercial power supply for the operation power supply. While a DC power supply device using AC power is used, when a power supply voltage of the DC power supply device drops, in a device using a lithium battery, a dummy load having a predetermined resistance value connectable to the lithium battery and a DC load of the unit are provided. A timer for measuring a use time using a power supply device, and a control switch for connecting the dummy load to the lithium battery and discharging for a predetermined discharge time when the time measurement result of the timer reaches a predetermined use time. An apparatus using a lithium battery characterized by having the following is obtained.

According to the present invention, there is provided an apparatus using the lithium battery, wherein the timer also counts the predetermined discharge time.

According to the present invention, there is provided an injection molding machine for detecting a position of a predetermined component by using an encoder and performing operation control based on the detection result, wherein the encoder is normally used as an operation power source. While using a DC power supply device utilizing commercial AC power, when the power supply voltage of the DC power supply device drops, in an injection molding machine using a lithium battery, a dummy load having a predetermined resistance connectable to the lithium battery, A timer for measuring the use time of the encoder using a DC power supply, and when the time measurement result of the timer reaches a predetermined use time, connect the dummy load to the lithium battery and discharge for a predetermined discharge time. And a control switch for performing the operation.

According to the present invention, there is provided the injection molding machine, wherein the timer also measures the predetermined discharge time.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below by using a DC power supply using commercial AC power as an operating power supply, and using a lithium battery when the power supply voltage of the DC power supply drops, to generate and / or use a signal. As an apparatus having a unit for storing data, an injection molding machine having an encoder will be described as an example.

The injection molding machine according to the present invention detects the position of a movable part such as a movable mold or a screw with respect to each reference position by using an encoder, and based on the detection result, plasticizes / meters, fills, and fills the resin. It controls the injection molding operation such as holding pressure and cooling / product removal.

FIG. 1 is a schematic diagram showing only an encoder part of an injection molding machine according to an embodiment of the present invention. FIG.
2, the encoder 1 requires power supply for its operation (generation of an encoded signal and / or temporary storage of encoded data), similarly to the conventional example shown in FIG. Normally, a power supply device 2 for converting commercial AC power to DC power of a voltage of 5 V is connected to the encoder 1. The encoder 1 itself has a function of monitoring the output voltage of the power supply device 2 and a function of switching the operation power supply based on the monitoring result.

The encoder 1 is normally operated by the power supply unit 2, but is operated by a power supply unit 2 due to a commercial AC power failure.
When the output voltage falls below a predetermined value, the power supply is switched from the power supply device 2 to the lithium battery 3, and the operation is continued. At this time, the encoder 1 continues to monitor the output voltage of the power supply device 2. Therefore, when the output voltage of the power supply device 2 is restored until the output voltage exceeds the predetermined value, the operation power supply is switched from the lithium battery 3 to the power supply device 2 again.

The present injection molding machine further measures a dummy load 14 having a predetermined resistance value (for example, 3.6 K ohms) connectable to a lithium battery and a use time of the encoder 1 using the power supply device 2. The timer 15 and the count result of the timer 15 indicate a predetermined use time (for example, several hundred to several thousand hours).
When the dummy load 14 is connected to the lithium battery 3 and discharge is performed for a predetermined discharge time (for example, 100 milliseconds).
And a control switch 16 for performing only Note that one end of the dummy load 14 is grounded. Also, the timer 15
Also measures a predetermined discharge time.

Next, the operation of the injection molding machine will be described.

In the operation of the injection molding machine, when the operation of the encoder 1 is started by the power supply device 2 using commercial AC power, the timer 15 sets the use of the encoder 1 by the power supply device 2 as a first time measurement operation. Start timing the time. At this time, the control switch 16 switches the lithium battery 3
It is connected to a standby terminal 16a that can be connected to the encoder 1 at any time.

The control switch 16 switches the connection of the lithium battery 3 from the standby terminal 16a to the discharge terminal 16b connected to the dummy load 14 when the time counted by the timer 15 reaches a predetermined use time. At this time, the timer 15
Resets the use time to zero and starts, as a second timing operation, the timing of the connection time between the lithium battery 3 and the dummy load 14, that is, the timing of the discharge time.

When the second timed result of the timer 15 reaches a predetermined use time, the control switch 16 turns on the lithium battery 3.
From the discharge terminal 16b to the standby terminal 16a again. At this time, the timer 15 resets the discharge time to zero and restarts the first timing operation.

The configuration relating to the lithium battery according to the present invention described above is not applied only to an injection molding machine having an encoder. For example, a machine tool having an encoder, or operating condition data or operation result data may be used. Applicable to all devices having a unit for performing signal generation and / or temporary storage of data using an operation power supply, such as a machine tool having a memory element for temporarily storing data by an operation power supply using a lithium battery. It is.

[0026]

The apparatus according to the present invention comprises a dummy load which can be connected to a lithium battery and has a predetermined resistance value, a timer for measuring the use time of an encoder using a DC power supply, and a timer for measuring the time. The battery has a control switch that connects a dummy load to the lithium battery when it reaches the use time, and discharges only for a predetermined discharge time, so a lithium battery that will not be used for a long time is used as the operating power supply. Even when the power supply voltage drops, it is difficult for the voltage drop to occur, and therefore, when the power supply voltage of the DC power supply drops, the unit that performs signal generation and / or data storage using a lithium battery hardly occurs.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a main part of an injection molding machine as an example of an apparatus according to an embodiment of the present invention, that is, an encoder part.

FIG. 2 is a schematic view showing an encoder part of a conventional injection molding machine.

FIG. 3 is a conceptual diagram for explaining an internal resistance increasing effect of a passivation film grown on an electrode in a lithium battery.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Encoder 2 Power supply device 3 Lithium battery 14 Dummy load 15 Timer 16 Control switch 16a Standby terminal 16b Discharge terminal R Internal resistance

Claims (4)

[Claims] 1. An apparatus having a unit for generating a signal and / or storing data by using an operation power supply, wherein the unit uses a DC power supply device which normally uses commercial AC power as its operation power supply. On the other hand, when the power supply voltage of the DC power supply drops, in a device using a lithium battery, a dummy load having a predetermined resistance value connectable to the lithium battery and a use time of the unit using the DC power supply are measured. A lithium battery, comprising: a timer, and a control switch for connecting the dummy load to the lithium battery when the time measurement result of the timer reaches a predetermined use time and performing a discharge for a predetermined discharge time. The equipment used. 2. The apparatus using a lithium battery according to claim 1, wherein the timer also counts the predetermined discharge time. 3. An injection molding machine for detecting the position of a predetermined component using an encoder and performing operation control based on the detection result, wherein the encoder normally uses commercial AC power as an operation power supply. In the injection molding machine using a lithium battery when the power supply voltage of the DC power supply is decreased while using the DC power supply used, a dummy load having a predetermined resistance value connectable to the lithium battery and the DC power supply are connected. A timer for measuring the use time of the encoder used, and a control switch for connecting the dummy load to the lithium battery and discharging for a predetermined discharge time when the time measurement result of the timer reaches a predetermined use time. An injection molding machine comprising: 4. The injection molding machine according to claim 3, wherein the timer also counts the predetermined discharge time.