JPS63133417A - Relay - 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 [Object of the Invention] (Industrial Application Field) The present invention relates to a relay used in a control circuit of a microwave oven or the like.

(Prior art) In a cooking device such as a microwave oven, a relay (DC relay) contact is inserted into the main circuit that supplies electricity to the magnetron.
The execution of cooking is controlled by turning on and off the relay.

Here, an example of a relay is shown in FIGS. 4 and 5.

1 is a DC relay, which is equipped with an L-shaped pedestal 2. An iron core 3 is erected at the bottom of the pedestal 2, and an excitation coil 4 is wound around the iron core 3. A movable plate 5 is provided on the standing portion of the pedestal 2 so as to face the upper end portion of the iron core 3. This movable plate 5 is made of iron and is attached to the upright part of the pedestal 2 so as to be able to move up and down.It receives an upward biasing force from a spring 6, and is normally moved away from the iron core 3. It has become.

Further, a movable contact piece 7 is provided on the movable plate 5, and a fixed terminal 8 is provided below the movable contact piece 7. The movable contact piece 7 is then connected to the fixed terminal 9. In other words, fixed terminal 8.
A normally open contact 10 is formed between 9 and 9.

Therefore, when a DC voltage Vdc is applied to both ends of the excitation coil 4, the iron core 3 is magnetized and the movable plate 5 is attracted to it. When the movable plate 5 is attracted, the movable contact piece 7 comes into contact with the fixed terminal 8, and electrical continuity is established between the fixed terminals 8 and 9. In other words, the normally open contact 10 is turned on. Furthermore, when the voltage application to the excitation coil 4 is released, the movable plate 5 separates from the iron core 3.
The movable contact piece 7 separates from the fixed terminal 8. In other words, electrical continuity between the fixed terminals 8 and 9 is broken, and the normally open contact 10 is turned off.

By the way, in a microwave oven, the magnetron's Rm
In addition to microwave cooking, some models also have an oven cooking function using heat generated by an electric heater, and as the number of functions increases, so does the number of relays.

However, if the number of relays is large, power consumption increases and a large power transformer must be used in the control section. This leads to an increase in cost, an increase in the size of the control circuit board on which the control section is mounted, and an increase in the size of the microwave oven itself.

(Problems to be solved by the invention) This invention was made in view of the above circumstances.
The purpose is to provide an excellent relay with low power consumption, which can prevent the power transformer from becoming larger.

[Structure of the Invention] (Means for Solving the Problems) The present invention includes an excitation coil, a contact that is driven by energizing the excitation coil, and means that moves with the contact to switch the number of turns of the excitation coil.

(Function) After the contact is driven, which does not require a large magnetomotive force, the number of turns of the excitation coil increases, the impedance increases, and the current is suppressed.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

First, a control circuit for a microwave oven according to the present invention is shown in FIG.

20 is a commercial AC power supply, and this power supply 20 is connected to a fuse 21°, a gnetron thermal 22. 1st door switch 23° 2nd door switch 24. Relay contact 55a, relay contact 5
The primary coil 25a of the high-voltage transformer 25 is connected to the normally open side of the high-voltage transformer 3a and the relay contact 51a in series. ^
The secondary coil 25b of the voltage transformer 25 has a high voltage capacitor 26. Discharge resistor 27. The anode and cathode of the magnetron 29 are connected through a half-wave voltage doubler rectifier circuit including a high-voltage diode 28.

30 is a grill heater, fuse 21. Magnetron thermal 22. First door switch 23. Second door switch 24. Relay contact 55a, normally closed side of relay contact 53a,
and is connected to the power supply 20 via the relay contact 51a in series. 31 is a hot air heater, fuse 21° magnetron thermal 22. 1st door switch 23° 2nd door switch 24. The power supply 20 is connected in series through the relay contact 54a, the normally closed side of the relay contact 53a, and the relay contact 51a.
connected to. A hot air fan motor 32 is connected in parallel to the hot air heater 31.

33 is a turntable drive motor, 34 is a magnetron cooling fan motor, and each has a fuse 21.7 magnetron thermal 22. It is connected to the electric power m2G via the first door switch 23° and the relay contact 52a in series.

35 is the door monitor switch, fuse 21.7 Gnetron thermal 22. and the first door switch 23 in series to the power supply 20. 36 is a heating indoor lighting lamp, so-called interior light, fuses 21.7 Gnetron thermal 22. and relay contact 51a in series!
Connected to 1li20.

On the other hand, 40 is a control section consisting of a microcomputer and its peripheral circuits, which performs overall control of the microwave oven. This control unit 40 has a power transformer 41 for receiving operating voltage, and the primary side of the power transformer 41 is connected to a fuse 21 and a magnetron thermal 22.
It is connected to the power supply 20 through the power supply 20 in series. The control unit 40 includes a door oven monitor switch 42, a heating room temperature sensor 43, a gas sensor 44, an operation display unit 45,
and DC low voltage relay of this invention 51.52.53.
54.55 are connected.

Here, the specific configuration of the relays 51, 52, 53, 54, 55 is shown in FIGS. 1 and 2.

Reference numeral 61 denotes a main body, which is provided with a 1-shaped pedestal 62. Pedestal 6
An iron core 63 is erected at the bottom of 2, and an excitation coil 64 is wound around the iron core 63. The excitation coil 64 has a terminal 65 on one end side, a terminal 66 on the other end side, and an intermediate terminal 67 in the middle part. coil 641).

A movable plate 68 is provided at the upright portion of the pedestal 62 so as to face the upper end of the iron core 63. This movable plate 68 is made of iron and is attached to the upright portion of the pedestal 62 so that it can move up and down. It has become. Further, a movable contact piece 70 is provided on the movable plate 68, and a fixed terminal 11 is provided below the movable contact piece 70. The movable contact piece 70 is then connected to a fixed terminal 72. In other words, the normally open contact 13 is formed between the fixed terminals 71 and 72.

Further, a contact piece 80 is provided on the movable plate θ8. This contact piece 80 contacts both the terminal 66 and the intermediate terminal 67 of the excitation coil 64 when deenergized, and separates from the terminal 6B when energized. In other words, a normally open contact 81 is formed at the terminal 68.671i1.

Note that when the relay 53 has a bidirectional contact, one more fixed terminal is added near the movable contact piece 70.

Next, the operation in the above configuration will be explained.

When a DC voltage Vdc is applied between the terminals 65 and 66, the exciting coil 64a is excited and the iron core 63 is magnetized.

In this case, when applying the DC voltage Vdc, the contact piece 80 contacts the terminals 66 and 67 and the normally open contact 81 is first in the on state, so the excitation coil 64 has an impedance of only the coil 64a. This allows a large current and exerts a large magnetomotive force on the iron core 63. When the iron core 63 is magnetized, the movable plate 68 is attracted to it.

When the movable plate 68 is attracted, the movable contact piece 70 is attached to the fixed terminal 7.
1, and the fixed terminals 71 and 72 are electrically connected. In other words, the normally open contact 73 is turned on.

Furthermore, when the movable plate 68 is attracted to the iron core 63, the contact piece 80
is separated from the terminal 66, and the normally open contact 81 is turned off. When the normally open connection a81 is turned off, the coil θ in the excitation coil 64
4b is turned on, and the impedance of the excitation coil 64 increases. This is done considering that a large magnetomotive force is not required to attract and hold the movable plate 68, and the excitation coil 64
This suppresses the current flowing to the

When the application of the DC voltage V, dc is removed, the magnetization of the iron core 83 is released, and the movable plate 68 is separated from the iron core 63. Then, the movable contact piece 10 separates from the fixed terminal 71, and the movable contact piece 10 separates from the fixed terminal 71.
．． Electrical continuity between 72 is broken. In other words, the normally open contact 13 is turned off.

In this way, when driving a contact that requires a large magnetomotive force, the impedance of the excitation coil 64 is made small to allow a large current, but when driving a contact that does not require a large magnetomotive force, the impedance of the excitation coil 64 is made large and a large current is allowed. Since the power consumption is suppressed, power consumption can be reduced. Therefore, even in a situation where a large number of relays are used as in the control circuit shown in FIG. 3, there is no need to make the power transformer 41 in the control section 40 large.

In other words, it is possible to suppress an increase in cost, and it is also possible to prevent the control circuit board on which the control section 40 is mounted from increasing in size, and by extension, the microwave oven main body from increasing in size.

In the above embodiment, the application to a control circuit of a microwave oven has been described, but the present invention can be similarly applied to a control circuit of other devices. In addition, the present invention is not limited to the above-mentioned embodiments, and various modifications can be made without changing the gist.

[Effects of the Invention] As described above, according to the present invention, an excitation coil, a contact that is driven by energization of the excitation coil, and a means that moves with the contact to switch the number of turns of the excitation coil are provided. Therefore, it is possible to provide an excellent relay that has low power consumption and can prevent the power transformer from becoming larger.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a diagram showing the same embodiment as an electric circuit, and FIG. 3 is a diagram showing the configuration of a control circuit of a microwave oven according to the embodiment. FIG. 4 is a diagram showing the configuration of a conventional relay, and FIG. 5 is a diagram showing the conventional relay as an electric circuit. 63... Iron core, 64... Excitation coil, 67... Intermediate terminal, 68... Movable plate, 70... Movable contact piece, 73
... Normally open contact, 8o... Contact piece, 81... Normally closed contact. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2

Claims (1)

[Claims] A relay comprising: an excitation coil; a contact driven by energization of the excitation coil; and means that moves with the contact to switch the number of turns of the excitation coil.