JPS6143831B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high frequency power switching device provided, for example, between a high frequency oscillator and a heating coil of a high frequency induction heating device having a plurality of heating coils.

In a high-frequency induction heating device, two or more heating coils are provided for one high-frequency oscillator, and the high-frequency power switching device switches the high-frequency power to perform heating work alternately.
This has often been done in the past due to the necessity of the heating and removal work cycle. Typical examples of the structures of conventional high frequency power switching devices include the rotary sliding type shown in FIG. 1 and the end face crimping type shown in FIG. In the rotary and sliding type shown in FIG. 1, the symbol 1 is a high frequency oscillator, 2 is a housing of a high frequency power switching device, 3 and 4 are heating coils, and 5 and 6 are movable switching contacts. Reference numeral 7 designates fixed contacts on the side of the movable switching contact 5, three of which are lined up on the same circumference, and are given the symbols H _l , H _f , and H _r for convenience of explanation of the operation to be described later. Similarly to 7, 8 is a fixed contact on the side of the movable switching contact 6, and is labeled L _l , L _f , and L _r . 9
is an insulating rod that mechanically connects the movable switching contacts 5 and 6, and a motor 10 is connected to the center thereof. As a result of the rotation of the motor 10, the fixed contacts H _f and H _l and L _f and L _l are connected by the movable switching contacts 5 and 6.
become conductive, or H _f and H _r and L _f and L
The structure is such that the high-frequency power from the high-frequency oscillator is switched depending on whether _{the r} and the high-frequency oscillator become conductive.
In this structure, the fixed contact 7 on the high voltage side (i.e. H
_f , H _l , H _r ) and the ground side fixed contact (i.e. L _f ,
L _l , L _r ) are located quite far from each other,
(One side of the output feeders F5 and F6 of the high frequency oscillator - F6 in Fig. 1 - is normally grounded in the high frequency oscillator.) The heating coil 3 is supplied from H _l and L _l , and the heating coil 4 is supplied from H _r . Since high frequency power must be supplied from L _r , the shape of the internal feeder of the housing 2 must be complicated. For example, in the connection state shown in FIG. 1 in which the heating coil 3 is energized, the feeders F5, F1, F2, and F6 surround a large area and generate a large magnetic flux when energized. Therefore, unless the casing 2 is made sufficiently large, a large amount of high-frequency magnetic flux will pass through the casing.
A portion of the housing will be heated by induction. Also,
Feeders F3 and F4 (F1, F2, F
5, F6 also has ground stray capacity,
In addition, for example, in a device with a high power of 100KW, the structure uses a pipe to flow cooling water inside, and the end of the pipe (not shown) is grounded through the cooling water conduit with high resistance. Therefore, it acts as a pick-up coil for the high-frequency magnetic flux generated on the current-carrying side, causing an induced current to flow through the heating coil 4, or applying a high voltage to a grounded part of the heating coil 4, such as the casing. In addition, in this structure, the electrostatic coupling between the non-energized side feeder and the energized side feeder is also large, which causes the non-energized side heating coil to have a high potential. In order to protect the safety of workers in the heating coil on the non-energized side,
It was necessary to provide sufficient means for short-circuiting and grounding the feeder on the non-current side near the exit from the housing. Furthermore, since the movable switching contact slides into contact with the fixed contact, each contact may wear out, resulting in poor contact between the contacts.

In addition, in the conventional end face crimping type shown in Fig. 2, 1 is a high frequency oscillator, 2 is a housing of a high frequency power switching device, 3 and 4 are heating coils, and 5 and 6 are movable switching contacts. Each has moving contacts H _f and L _f . 7 is a fixed contact on the heating coil 3 side, 8 is a fixed contact on the heating coil 4 side, and the high voltage side H
Label _l , H _r , and ground side L _l and L _r . 9
is a flexible feeder connected to a moving contact H _f , 10 is a flexible feeder connected to a moving contact L _f similar to 9, and 11 and 12 are flexible feeders connected to a moving contact L f, respectively. It is a double-axis cylinder for movement, and these cylinders are simultaneously moved in the same direction by pneumatic or hydraulic pressure, and H _l and H _f and L _l and L _f are brought into contact, respectively, or H _f and H _r are brought into contact with each other. By bringing L _r and L _f into contact with each other, high frequency power is switched and supplied to the heating coil 3 or the heating coil 4. This type also has the same drawbacks as the rotary and sliding type. Further, the flexible feeders 9 and 10 may be damaged as a result of repeated bending.

As mentioned above, the present invention solves the problem of induction heating of the housing of a high-frequency power switching device due to leakage magnetic flux, wear of contacts due to sliding, or damage due to repeated use of flexible feeders, and also solves the problem of heating the housing of a high-frequency power switching device due to leakage magnetic flux. This was done with the purpose of completely preventing induction of high voltage into the coil, and will be explained in detail below.

As an embodiment of the present invention, FIG. 3 shows a configuration diagram of the main parts of a high-frequency power switching device in a case where one high-frequency oscillator has two heating coils. In the figure, 1 is a high-frequency oscillator, 2 is a housing of a high-frequency power switching device, 3 and 4 are heating coils, 5 is a movable switching contact on the high voltage side, and 6 is a movable switching contact on the ground side. Figure 3 shows movable switching contacts 5 and 6.
indicates that the heating coil 3 is energized. Reference numeral 7 denotes a fixed contact provided between an insulating plate 10 (selected from a material with low dielectric constant and high frequency loss and high dielectric strength), and for convenience of explanation below, H _l and H are provided on the high voltage side. _f , H _r , L on the ground side
Add the signs _l , L _f , and L _r . 8 and 9 electrically short-circuit the high-voltage side fixed contact and the grounding side fixed contact, which are in a non-energized state, by the contact at the center, and when they are on the energized side, the center contact is separated from the fixed contact. A ground plate spring that contacts the housing,
Both ends are fixed to the movable plate 14. In FIG. 3, the ground plate spring 8 is in contact with the housing 2, and the ground plate spring 9 short-circuits the fixed contacts H _r and L _r . 11 is a support rod of the movable switching contact 5, and 12 is an insulating plate that insulates the contact part conductor of the movable switching contact 5 from the support rod 11. Reference numeral 13 denotes a support plate into which the support rod 11 of the movable switching contact 5 is loosely fitted, and is attached to the movable plate 14 via a link 15 and a spring 20. 16 is a roller attached to both ends of the support plate 13, 17 is a stopper attached to the housing, and 18 is a moving plate 14.
19 is a coil spring along which the guide shaft moves. The moving plate 14 is driven by an air cylinder 21 via a piston rod 23. 22 is a solenoid valve that switches the air pressure supplied to 21. Note that the mechanism for moving the movable switching contact 6 is vertically symmetrically arranged as shown in FIG. 3, so a description thereof will be omitted.

FIG. 4 is a diagram showing the arrangement of electrodes and the connection of the feeder when FIG. 3 is viewed from below. Among the movable switching contact 5 and the fixed contact 7, H _l , H _f , and H _r are as follows:
They are located on the back side of the insulating plate 10 at positions facing the movable switching contact 6 and the fixed contacts L _l , L _f , and L _r, respectively. In addition, in FIG. 3, the attachment of the feeder from the heating coil 3 to the fixed contacts H _l and L _l and the attachment of the input feeder to the fixed contacts H _f and L _f are illustrated in the horizontal direction for convenience. In this way, the input and output feeders are actually attached to the fixed contact from opposite directions.

As is clear from FIGS. 3 and 4, the fixed contact 7 is a plate-shaped conductor, and its high-voltage side and ground side face each other at a narrow interval with an insulating plate 10 in between, and the movable switching contact 5 and Since the conductor parts 6 are also facing each other at a short distance, most of the magnetic flux generated by energization is localized near these conductors, and the length of the part inside the input/output feeder housing is also short. It is possible to extremely reduce the magnetic flux penetrating the casing when energized, and it is extremely rare for a part of the casing to be heated by high-frequency induction even when a large power of several hundred kilowatts or more is applied. Therefore, it is possible to reduce the size of the casing to a size that is as close as possible to the size of the stored object. In addition, the high voltage side fixed contact on the non-energized side and the ground side fixed contact are short-circuited by a ground plate spring, and the movable plate 14
is grounded to the housing via another ground leaf spring, so that no voltage can be transferred between the fixed contacts or between the fixed contacts and the housing by electromagnetic coupling or capacitive coupling (both have small conductor arrangements). Even if it occurs, it will not apply a high potential to the de-energized heating coil.

Next, the operation of this high frequency power switching device will be explained. Generally, when switching the heating coil to be energized in a high-frequency induction heating device, if one of the heating coils is energized, first stop the high-frequency oscillator by operating a switch on the operation panel (not shown) before turning on the changeover switch. into the heating coil side. That is, the switching is performed while the high frequency oscillator is stopped. For convenience of explanation, a case will be described in which the heating coil 3 side on the left side shown in FIGS. 3 and 4 is switched to the heating coil 4 side on the right side.
In FIG. 3, compressed air is supplied to the air pipe P ₁ side through the solenoid valve 22, and the air from the air pipe P ₂ side is released, so as a result of the operation of the air cylinder 21, the movable plate 14 moves as shown in the figure. It is placed all the way to the left. Therefore, the roller 16 at the left end of the support plate 13 is pressed against the stopper 17, and the operation of the link 15 causes the support plate 13 to approach the movable plate 14.
The movable switching contact 5 is pressed against the fixed contact 7 by the elasticity of the coil spring 19. Therefore, when the changeover switch on the operation panel is set to the heating coil 4 side, the solenoid valve 22
moves downward, the air on the air _P1 side escapes, and the air pipe
Compressed air is supplied to the _P2 side, and the air cylinder 21 is actuated to move the moving plate 14 connected to the piston rod 23 to the right along the guide shaft 18. At this time, due to the action of the spring 20 and the link 15 being triggered, the link 15 is moved to the movable plate 1.
4, and the support plate 13 moves away from the movable plate 14. Therefore, the support plate 13 pushes up the support rod 11, and the movable switching contact 5 can move away from the fixed contacts H _l and H _f without sliding on the fixed contact 7.
Then, when the movable plate 14 moves to the right and the roller 16 at its right end hits the stopper 17 on the right side of the housing 2 and stops, the movable plate 14 further moves to the guide shaft 18.
By moving slightly to the right along , the roller 16 moves along the stopper 17 and the link 1
5 is tilted, the support plate 13 is drawn toward the movable plate 14, and the elasticity of the coil spring 19 causes the movable switching contact 5 to act vertically toward the fixed contacts H _f and H _{r .}
and H _r , and the switching of the high pressure side feeder is completed. Moreover, since the compressed air from the solenoid valve 22 is simultaneously supplied to the two upper and lower air cylinders 21, the switching of the movable switching contact 6 is completed at the same time as the switching of the movable switching contact 5 is completed.
In addition, in FIG. 3, the ground plate spring 9 short-circuits the fixed contacts H _r and L _r on the non-current-carrying side, and is electrically grounded to the housing 2 by the earth plate spring 8 via the movable plate 14. However, as the movable plate 14 moves, the ground plate spring 8 separates from the casing, and the ground plate spring 9 separates from the fixed contacts H _r and L _r , and when the switching is completed, the earth plate spring 8 becomes non-contact. By short-circuiting the fixed contacts H _l and L _l , which have become energized, and bringing the ground plate spring 9 into contact with the casing 2 , the fixed contacts H _l and L _l are grounded via the movable plate 14 .

Note that the embodiment of the present invention is not limited to the embodiment shown in FIG. 3 in which the switching operation is performed by moving the movable switching contact from side to side. For example, it is also possible to employ a structure in which the linearly arranged fixed contacts are arranged in a fan shape, and the movable switching contact is driven by a motor or the like to perform the switching operation by rotation. In this case, the parts corresponding to the moving plate 14 and the support plate 13 in FIG. 3 have a disk-like or annular shape (or a part thereof).
Therefore, in order to press and release the movable switching contact, it is convenient to use a cam mechanism instead of the link mechanism shown in FIG. Also, in Fig. 3, the ground plate spring is in contact with the outer surface of the fixed contact, but
There is no need to limit it to this, and it is also possible to adopt a structure in which it contacts the upper side of the fixed contact. Furthermore, if it is necessary to switch and feed power to three or more sets of feeders, in addition to using a combination of multiple high-frequency power switching devices for two sets of feeders according to the present invention,
For example, a structure in which two or more fixed contacts of the input feeder and three or more sets of fixed contacts of the output feeder are arranged on the circumference and rotary movable switching contacts are used, or the fixed contacts of the input feeder are annular and the outside This can be easily realized by arranging the fixed contacts of the output feeder on the circumference and using a rotating movable switching contact.

As is clear from the above description, in the high frequency power switching device embodying the present invention, the fixed contact groups are arranged facing each other on both sides of a single insulating plate, so that high frequency high power can be supplied. Also, the casing is rarely subjected to high-frequency induction heating, and the casing can be made smaller. In addition, the voltage induced in the fixed contact or feeder on the non-current-carrying side due to some electromagnetic coupling or electrostatic coupling is effectively short-circuited and grounded, so it is safe without applying a high potential to the heating coil on the non-carrying side. Further, since the movable switching contact does not press or detach vertically from the fixed contact and slide, it is possible to provide a highly reliable high-frequency power switching device without fear of wear.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of the configuration of a conventional rotary sliding type high-frequency power switching device, FIG. 2 is a diagram showing an example of the configuration of a conventional end face crimping type high-frequency power switching device, and FIG. 3 is a configuration example of a high-frequency power switching device according to the present invention. An example diagram, FIG. 4, is a diagram showing the arrangement of electrodes and the connection of the feeder when viewed from below in FIG. 3. In Fig. 3, 1...high frequency oscillator, 2...
Housing, 3, 4... Heating coil, 5, 6... Movable switching contact, 7... Fixed contact, 8, 9... Earth plate spring, 10... Insulating plate, 11... Movable switching contact. Support rod, 12... Insulating plate, 13... Support plate, 1
4...Moving board, 15...Link, 16...Koro,
17... Stopper, 18... Guide shaft, 19...
Coil spring, 20... Spring, 21... Air cylinder, 22... Solenoid valve, 23... Piston rod.

Claims (1)

[Claims] 1. One or more fixed contacts connected to one terminal of a feeder on the power supply side, and a plurality of fixed contacts connected to one terminal of each feeder on the load side. Further, on the opposite side of the insulating plate, fixed contacts connected to the other terminals of the feeder on the power supply side and the load side are provided so as to face each of the fixed contacts, and the above-mentioned A high-frequency power switching device characterized in that movable switching contacts are provided on each side of an insulating plate to switch and connect a power supply side fixed contact and a load side fixed contact. 2. The high frequency device according to claim 1, wherein the movable switching contact is configured to move with a gap maintained relative to the fixed contact, and then move in a vertical direction with respect to the fixed contact and come into contact with the fixed contact. Power switching device. 3. Claim 1, characterized in that a mechanism is provided for short-circuiting and grounding two opposing fixed contacts connected to a load-side feeder that is not supplied with power in conjunction with the switching operation. High frequency power switching device.