JPH0512671Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a control circuit for a separate air conditioner, and in particular aims to improve the safety of the connection line connecting an indoor unit and an outdoor unit. It is.

<Prior art> In an air conditioner, especially a separate air conditioner consisting of an indoor unit and an outdoor unit, connection of communication lines (power lines and signal lines) connecting the indoor unit and outdoor unit is done during the installation of the air conditioner. Sometimes electric wires, mostly VVF cables (commonly known as VA) according to JIS
Electrical work is carried out using cables (cables), etc., and is carried out on terminal boards for connection of communication lines provided in each indoor and outdoor unit. Among these connection lines, most of the current consumption of the air conditioner, for example, a large current of 15A to 20A, flows through the power line in particular, so if there is a poor connection at the connection part of the connection line, it may temporarily can be operated without any problems, but as operation continues, the poor contact area becomes hot due to abnormal heat generation due to the large current, thermally deforming the surrounding resin parts, and furthermore, arcing occurs at the poor contact area, leading to ignition. There is a possibility that. In particular, the rate of occurrence of connection failure accidents varies depending on the structure of the connection terminal board and the mounting position of the terminal board, ie, the ease of connection line connection work. For example, if the terminal board has a screw-fastened structure, poor contact may occur if the screws are not tightened enough or if the screws are forgotten. In addition, for insertion type connectors that do not use screws, so-called quick connection type connectors, insufficient insertion can be cited as a cause of poor contact.

Based on the premise that defects in connection line connection work are likely to occur, a temperature sensor such as a temperature fuse is installed near the connection terminal board of the connection line in order to completely prevent accidents such as fire due to connection failure. In the unlikely event that the connection wire becomes hot due to a poor connection, a system has been put into practical use that shuts off the power to the compressor to prevent heat generation and fire caused by the large current. This conventional device is shown in FIG. Note that FIG. 4 is a schematic diagram, and other than the main points are omitted.

Reference numeral 5 denotes a power plug, from which commercial power is supplied, to the terminals of the connection terminal board (indoor) 6, and to the terminals of the connection terminal board (outdoor) 7 with connecting wires (power lines) 24-1, 24-2. ′, ON−
It is supplied to the compressor 9 via the contacts of the OFF control relay 8. 21 is a condenser for operating the compressor 9. On the indoor unit side, a low-voltage power source is supplied by a transformer 10 to terminals 13 and 14 of a control circuit 11, and a rectifier and constant voltage circuit provided inside the control circuit 11 serves as a power source for the control circuit, and the internal elements and ICs are supplied with power. and microcomputers. Signals are output from the terminals 12a and 12b of the control circuit 11, and the terminals of the connection terminal board (indoor) 6, communication lines (signal lines) 24-3, 24-4,
The terminals 19a, 19 of the control circuit 16 of the outdoor unit are connected via the terminals ′, ′ of the connection terminal board (outdoor) 7.
connected to b. Commercial power is supplied to terminals ', ' of the connection terminal board (outdoor) 7. A power source reduced in voltage by a transformer 15 connected to a commercial power source is supplied to terminals 17 and 18 of a control circuit 16, and serves as a power source for driving the control circuit 16 via an internal rectifier circuit and a constant voltage circuit. The output from the terminal 20 of the control circuit 16 controls ON/OFF of the compressor 9 via the contact of the control relay 8. 22,2
Reference numeral 3 denotes a temperature sensor such as a temperature fuse, and connecting wires (power wires) 24-1, 24 among the terminal boards 6, 7 for connecting the indoor unit and outdoor unit.
-2 is located at a position where it is affected by heat from the terminals ,',', which are the connection parts.

The operation of the above configuration will be explained below. When the indoor unit's connection terminal board 6 has a poor connection or a connection, the compressor 9 generates abnormal heat due to the large current generated and the temperature reaches a high temperature, the temperature sensor (temperature fuse) 22 is activated. The wire breaks. Since the low voltage power source of the transformer 10 is connected to the terminal 13 of the control circuit 11 via the temperature sensor (temperature fuse) 22 in series, the power supply to the control circuit 11 is stopped. Control circuit 1
1 does not operate, the control circuit 1 of the outdoor unit
Signal input to terminals 19a and 19b of 6 is also stopped. Therefore, the signal for driving the control relay 8 is not output, the compressor 9 is stopped, and the large current is also stopped.

Next, the terminal ' of the terminal board 7 for connection of the outdoor unit.
Alternatively, if there is a poor connection at the connection point '', the temperature sensor (temperature fuse) 23 connected in series with the low voltage power supply of the transformer 15 operates due to the high temperature, and the power supply to the control circuit 16 is stopped. Therefore, the control relay 8 cannot be driven and the compressor 9 is stopped. In this way, an attempt is made to prevent accidents such as fires due to poor connection of the connection line.

<Problems to be solved by the invention> However, in the conventional example shown in FIG. Connection lines 51, 52, 53, 54 from the control circuits 11, 16 to 22, 23 are required. Although the transformers 10 and 15 are shown outside the control circuits 11 and 16 in FIG. 4, this is for convenience of explanation, and in reality, the transformer 10 and the control circuit 11 are shown outside the control board section of the indoor unit. (not shown), and the transformer 15 is connected to the control circuit 1
6 and is arranged on the control board section (not shown) on the outdoor unit side. That is, the connection wires 51 and 52 run from the control board on the indoor unit side to the connection terminal board 6 on which the temperature sensor 22 is disposed, and the connection wires 51 and 52 run from the control board on the outdoor unit side to the temperature sensor 23.
The connection wire 53 to the connection terminal board 7 provided with
54 is required. In addition, the connection terminal board 6
is arranged inside the indoor unit, and the connection terminal board 7 is arranged inside the outdoor unit.

The terminals of these connection terminal boards 6, 7 [,,
, ], [',',','] to the respective control boards of the indoor unit and outdoor unit, as well as connecting wires 51, 52, 53, and 54 from the temperature sensors 22 and 23. This is making the electrical components of indoor (outdoor) units more complex, as space is limited in an effort to make them even thinner.

This invention solves the above conventional problems,
Even if a temperature sensor is provided, it is not necessary to add a separate connection line for that purpose, and the purpose is to prevent fires due to poor connection of the communication line with a simple configuration.

<Means for Solving the Problems> In order to achieve the above object, this invention provides a connection between the indoor unit and outdoor unit in the control circuit of a separate air conditioner consisting of an indoor unit and an outdoor unit. A temperature sensor is connected in series to the signal line of the wires, and the temperature sensor is placed in a position where it is easily affected by heat from the connecting part of the connecting line that connects to the compressor of the connecting terminal board of the connecting line. , and the temperature sensor is inserted between the connection terminal of at least one signal line of the connection terminal board and the relay terminal.

<Function> If abnormal heat is generated due to a poor connection in the connection line, the resistance value will increase if the temperature sensor is of a type that changes resistance, such as a positive temperature coefficient thermistor, and the contact will change if the contact is open/closed, such as a bimetal switch. If it is a temperature sensor, the contacts open and the resistance value becomes infinite, the signal output from the control circuit of the indoor unit is no longer input to the control circuit of the outdoor unit, the compressor stops, the abnormal heat generation subsides, and a fire occurs. etc. can be prevented.

<Example> An example of the present invention will be described below with reference to the drawings. First, an overview of the air conditioner used in the embodiment of the present invention will be explained with reference to FIG. The air conditioner is a refrigerant compression type, and 1 is a compressor that compresses the refrigerant, 2 is a condenser that condenses the refrigerant, 3 is a pressure reducer that reduces the pressure of the refrigerant, and 4 is an evaporator that evaporates the refrigerant. Although not included, each of the condenser and evaporator is provided with a blower device that blows air for heat exchange, and the above configuration performs cooling operation.

Next, a control circuit according to an embodiment of the present invention will be explained with reference to FIGS. 2 and 3. Note that FIGS. 2 and 3 are schematic diagrams, and other than the main points are omitted. Also, the same parts as in Fig. 4 of the conventional example are given the same numbers.
The explanation will mainly focus on the differences from the one shown in FIG. In FIG. 2, the temperature sensor 22 is connected at one end to a terminal of the connection terminal board (indoor) 6 and at the other end to the terminal 12a of the control circuit 11. Of course, the relay terminal 6a can also be provided within the connection terminal board (indoor) 6. Similarly, the temperature sensor 23 has one end connected to the terminal ' of the connection terminal board (outdoor) 7 and the other end connected to the terminal 19a of the control circuit 16. Relay terminal 7
a can also be provided inside the connection terminal board (outdoor) 7. The low-voltage power supplies for the transformers 10 and 15 are connected to the control circuit 1 without going through the temperature sensors 22 and 23.
It is connected to terminals [13, 14] and [17, 18] of terminals 1 and 16. By connecting as described above, the number of connection lines from the control board section to the temperature sensors 22, 23 near the connection terminal plates 6, 7 can be reduced.

Next, the operation of the temperature sensors 22 and 23, which is the main point, will be explained in detail with reference to the circuit diagram of the signal line section in FIG.

First, 25 is the positive side power supply of the low voltage DC power supply of the control circuit 11 of the indoor unit, which connects the terminal 12a of the control circuit 11 to the temperature sensor 22 on the indoor side, the terminal, the communication line (signal line) 24-3, the terminal ', the indoor It enters the control circuit 16 of the outdoor unit from the terminal 19a through the outside temperature sensor 23, the current limiting resistor 26, and the light emitting diode 2 in the photocoupler 27.
7a, terminal', connection line (signal line) 24-
It enters the control circuit 11 of the indoor unit again through the terminal 2 and terminal 12b, and is connected to the negative power supply of the control circuit 11 through the collector and emitter of the transistor 28. transistor 28
The output port 30 of the microcomputer 29 (on the indoor side) is connected to the base of the microcomputer 29 via a resistor 31.
The positive side power supply 32 of the low voltage DC power supply in the control circuit 16 of the outdoor unit is connected to the negative side power supply of the control circuit 16 through the collector and emitter of the phototransistor 27b of the photocoupler 27 via the resistor 33, and the emitter of the phototransistor 27b. The connection point between the resistor 33 and the input port 35 of the microcomputer 34 (on the outdoor side) is connected.
With the above configuration, signals are transmitted from the indoor unit to the outdoor unit. The operation will be explained below. Transmission is performed as a serial signal in synchronization with a certain period. For example, when a "HIGH" level is output from the output port 30 of the microcomputer 29 of the indoor unit, the transistor 28 is turned on (conducted), the light emitting diode 27a of the photocoupler 27 in the control circuit 16 of the outdoor unit emits light, and the phototransistor 27b turns on. Turns on (conducts). Therefore, the input port 35 of the outdoor unit's microcomputer 34 has a "HIGH" level.
A level signal is input. Conversely, when the output port 30 of the microcomputer 29 of the indoor unit is set to the "LOW" level, the transistor 28 is turned off (opened), and no current flows to the light emitting diode 27a of the photocoupler 27, so it does not emit light, so the phototransistor 27b
is turned OFF (open), and a "LOW" level signal is input to the input port 35 of the microcomputer 34 of the outdoor unit. The microcomputers 29 and 34 of the indoor unit and the outdoor unit synchronize the above operations and transmit serial signals. Possible synchronization methods include power supply frequency, a timer built into a microcomputer, and other methods, but these are omitted in FIGS. 2 and 3 because they are not directly related to the present invention. The information sent from the indoor unit to the outdoor unit may include ON/OFF data of the compressor 9 and other various information. For example, when the microcomputer 34 of the outdoor unit receives an OFF signal from the compressor, it outputs an OFF signal from the output port 36 to the control circuit 16 of the outdoor unit.
output through the terminal 20 of the control relay 8.
OFF (open) and stop the compressor 9. When the microcomputer 34 receives the compressor ON signal, it turns on the control relay 8 and operates the compressor 9.

As the temperature sensors 22 and 23, temperature fuses, bimetal switches, positive temperature coefficient thermistors, etc. can be used. Temperature fuses operate once and do not recover once they are blown, but bimetal switches and positive temperature coefficient thermistors recover when the temperature drops.

If the contact line (power line) 24-1 or 24-2 generates abnormal heat due to a poor connection at the terminal of the connection terminal board (indoor) 6, the temperature sensor 22 is activated, the resistance value increases, and light is emitted. In order to reduce the current flowing through the diode 27a, the photocoupler 27 is no longer turned on. Therefore, only a "LOW" level signal is input to the input port 35 of the microcomputer 34 of the outdoor unit. In terms of form, when the temperature sensor 22 operates, it operates in the direction of blocking signal transmission from the indoor unit to the outdoor unit.
For example, if the microcomputer 34 of the outdoor unit can normally receive signal data for a certain period of time, that is,
If only a "LOW" level signal is input, the compressor is stopped and the communication line (power line) 24-1,
This is to stop the large current flowing through 24-2 and prevent accidents such as ignition due to abnormal heat generation.

Regarding the operation after the compressor is stopped, for example, the compressor will not be operated (ON) again unless the power is turned OFF and the microcomputer 34 is reset, or the operation will be restarted if the signal data starts entering normally again after a certain period of time. Possible solutions include restoring it to the state of

The operation of the temperature sensor 23 is also similar to the operation of the temperature sensor 22 described above, so the explanation will be omitted.

The temperature sensors 22 and 23 are attached to positions exposed to heat from the terminals [,] and [','] portions of the connection terminal board.

[Effect of idea]

As is clear from the above description of the embodiments, the present invention uses a temperature sensor to detect abnormal heat generation due to a poor connection from the connecting part of the connecting line connecting to the compressor on the terminal board for connecting the connecting line. prevent it from happening. In addition, the connection line to the temperature sensor also serves as the connection line to the communication line (signal line), and the same effect can be achieved without adding a special connection line for the temperature sensor.
The electrical equipment section, which has limited space, has been simplified.

[Brief explanation of the drawing]

Fig. 1 is a refrigeration cycle diagram for explaining the outline of an air conditioner used in an embodiment of the present invention, Fig. 2 is a control circuit outline portion of an embodiment of the present invention, and Fig. 3 is an embodiment of the present invention. FIG. 4 is a schematic diagram of a control circuit of a conventional example. 24... Communication line, 24-1 and 24-2... Communication line (power supply line) connected to the compressor, 24-3 and 24-4... Signal line among the communication lines, 22 and 2
3... Temperature sensor, 9... Compressor, 6 and 7...
...Connection terminal board, 11 and 16...control circuit.

Claims (1)

[Scope of Claim for Utility Model Registration] In a control circuit for a separate air conditioner consisting of an indoor unit and an outdoor unit, a temperature sensor is installed in series with a signal line of the communication line connecting the indoor unit and outdoor unit. At the same time, the temperature sensor is placed in a position where it is easily affected by heat from the connection part of the connection line connected to the compressor of the connection terminal board of the connection line, and the temperature sensor is placed in the connection terminal board of the connection line. A control circuit for an air conditioner, characterized in that it is inserted between a terminal for connecting at least one signal line and a relay terminal (for example, between a terminal and a terminal 6a).