JP4646782B2 - Electromagnetic safety valve - Google Patents

Description

  The present invention relates to an electromagnetic safety valve for closing a gas supply to a burner when the burner misfires.

  This type of electromagnetic safety valve is used to shut off the supply of gas to the burner if the burner misfires. In order to detect that the burner has misfired, a thermocouple is placed in the vicinity of the burner, and if a thermoelectromotive force is not output from the thermocouple, or if the thermoelectromotive force voltage drops below a predetermined voltage, a misfire is detected. To be judged. Although there is a type in which the thermoelectromotive force is input to the microcomputer and the electromagnetic safety valve itself is opened and held by the valve opening holding current supplied from the microcomputer, the thermoelectromotive force is directly supplied from the thermocouple and the internal excitation coil is heated. There is a type in which a fixed iron core is excited by flowing a current due to an electromotive force (see Patent Document 1).

  In the case where the thermoelectromotive force is directly supplied from the thermocouple to the exciting coil, the current value of the thermoelectromotive force is low, but the current value is large. It is characterized by a small number of windings. Therefore, a lead wire is wound around a dummy winding core in advance to form an excitation coil, and then the excitation coil is removed from the dummy winding core to create an air-core excitation coil. It is mounted on the magnetic pole of the fixed iron core.

Also, a hollow pipe-shaped external electrode protrudes outward from the electromagnetic safety valve, and the lead wire of the excitation coil attached to the magnetic pole of the fixed iron core is inserted into the external electrode from the inside to the outside. The lead wire and the tip of the fixed iron core are welded at the tip of the wire. In addition, the opening of the external electrode is closed at the welded portion to make it airtight, and an annular sealing member is attached to the outer peripheral portion of the external electrode to ensure sealing performance.
Japanese Patent Laid-Open No. 9-100990 (FIG. 1)

  In the conventional device described in Patent Document 1, the external electrode is hollow, and a lead wire must be inserted inside, so that the diameter of the external electrode must be secured to some extent. For this reason, when the electromagnetic safety valve is downsized, the external electrode hinders downsizing. Also, the lead wire is welded at the tip of the external electrode. If the sealing of the hole at the tip of the external electrode is incomplete during welding, the inside of the electromagnetic safety valve is connected to the outside via the external electrode. Troubles such as communication.

  Further, in the type in which the thermoelectromotive force from the thermocouple is directly supplied to the exciting coil, the exciting coil is formed in an air-core state, so that the lead wire can be wound only once. Therefore, if you want to increase the number of turns of the exciting coil to increase the electromagnetic force of the fixed iron core, the length of the exciting coil becomes longer and the magnetic pole of the fixed iron core has to be extended, which also hinders the miniaturization of the electromagnetic safety valve Will do.

  Then, this invention makes it a subject to provide the electromagnetic safety valve which can eliminate the above-mentioned malfunction in view of said problem.

In order to solve the above problems, an electromagnetic safety valve according to the present invention is mounted on at least one of a U-shaped fixed iron core housed in a metal holder member and a magnetic pole of the fixed iron core, and an exciting coil is wound around it. The movable iron core is attached to the fixed iron core by energizing the exciting coil through an electrode whose one end penetrates the holder member and is exposed to the outside and the other end is not exposed to the outside of the electromagnetic safety valve. In an electromagnetic safety valve that holds and holds the valve body connected to the movable iron core in a valve-open state, the round bar-shaped electrode that is not hollow is bent in an L shape, and the bent portion is buried in the bobbin. Is held on the bobbin, the other end of the electrode is exposed from the bobbin, and a connecting portion to which the lead wire drawn from the exciting coil is connected to the other end is formed. in between the In order to mount the seal member, the connecting section and the holder member located within the electromagnetic safety valve by the cross-sectional shape of the electrode is provided with a seal mounting portion of the left circular, mounting the annular sealing member to the seal mounting portion Sealing is performed at a position between the electrode and one end of the electrode exposed to the outside .

  By winding the exciting coil around the bobbin, the lead wire of the exciting coil can be wound in multiple layers. Further, a round bar-shaped electrode was used instead of the conventionally used hollow external electrode. As a result, the exciting coil can be downsized and the external electrode can be downsized, and there is no problem that the inside of the electromagnetic safety valve communicates with the outside through the inside of the external electrode.

  By the way, when an external thermocouple is connected to the exciting coil, the lead wire of the exciting coil becomes thick. On the other hand, when a round bar electrode is employed, it is necessary to connect the lead wire of the exciting coil to the electrode inside the electromagnetic safety valve. In order to mount an annular seal member on the electrode, at least the cross section of the seal mounting portion needs to be circular. However, when the cross section is circular, the cross section of the lead wire is also circular. Cannot position well. In particular, when the lead wire of the exciting coil becomes thick, the tendency becomes remarkable. Therefore, a substantially planar connection portion is formed on the electrode so that the lead wire can be easily connected to the electrode.

  In addition, if the substantially planar connecting portion is bent along the direction in which the lead wire extends, the contact area between the lead wire and the connecting portion further increases, and the lead wire can be more easily connected to the connecting portion. can do.

  As is apparent from the above description, the present invention conventionally uses a hollow external electrode, but the electromagnetic safety valve can be miniaturized by replacing it with a round bar electrode. Furthermore, even for the type that directly supplies the thermoelectromotive force from the thermocouple to the excitation coil, it is possible to perform multi-layer winding by winding the excitation coil around the bobbin. Even if it is configured so as to obtain an attractive force, it can be made smaller than the conventional one. In addition, although the cross-sectional shape of the electrode is circular, the connection between the electrode and the lead wire can be easily performed because the substantially planar connection portion is formed at the inner end of the electrode.

  1 and 2, reference numeral 1 denotes an electromagnetic safety valve according to the present invention. The electromagnetic safety valve 1 includes a U-shaped fixed iron core 2 made of a magnetic material. The fixed iron core 2 is housed in a metal holder member 21 and the exciting coil 3 is attached to one magnetic pole.

  The exciting coil 3 includes a resin bobbin 31 and a lead wire 32 wound around the bobbin 31. In the present embodiment, a thermoelectromotive force from a thermocouple (not shown) is directly supplied to the exciting coil 3. The lead wire 32 was wound around the bobbin 31 16 times in three stages.

  The bobbin 31 held a round bar-shaped electrode 4. The electrode 4 is bent in an L shape, and the bent portion is held so as to be buried in the bobbin 31. One end 41 of the electrode 4 extends so as to be exposed to the outside of the electromagnetic safety valve 1, and the anode of the thermocouple is connected to the one end 41. On the other hand, one end 32 a of the lead wire 32 is connected to the other end 43. The other end 32 b of the lead wire 32 is connected to the holder member 21, and is grounded to a mounting body (not shown) via the flange 22 and connected to the cathode of the thermocouple. As a result, the thermoelectromotive force supplied from the thermocouple flows to the exciting coil.

  When a current flows through the exciting coil 3, the fixed iron core 2 is excited. At that time, if the movable iron core 11 is pressed against the magnetic poles of the fixed iron core 2, the movable iron core 11 remains adsorbed on the fixed iron core 2. Since the movable iron core 22 is connected to the valve body 12 of the on-off valve, the state of being opened is maintained. When the thermoelectromotive force from the thermocouple disappears or the current value falls below a predetermined value, the movable iron core 11 is detached from the fixed iron core 2 and the valve body 12 moves to the valve closing position as in the conventional case. is there.

  An O-ring 5 that is an annular seal member is attached to the electrode 4. In the present embodiment, the electrode 4 is formed by cutting a wire having a circular cross-sectional shape into a predetermined length and bending the wire into an L shape. Reference numeral 42 (range indicated by cross-hatching) is a seal mounting portion.

  However, since the cross-sectional shape of the lead wire 32 is also circular, if the cross-sectional shape of the other end 43 is also circular, it is difficult to connect the one end 32 a of the lead wire 32 to the other end 43 of the electrode 4. Therefore, as shown in FIG. 3, the other end 43 is pressed from above and below to form a planar connection portion 43a at least at the top. As shown in FIG. 3, one end 32a of the lead wire 32 is positioned on the connecting portion 43a, and the one end 32a of the lead wire 32 is connected to the electrode 4 by spot welding, laser welding, arc welding, or soldering from above. Connected to the other end 43.

  The shape of the other end 43 is not limited to that shown in FIG. 3. For example, as shown in FIG. 4A, the other end 43 extends along the extending direction of the one end 32 a of the lead wire 32. You may bend in. Alternatively, as shown in FIG. 5B, the other end 43 may be folded back 180 degrees, and the one end 32a of the lead wire 32 may be sandwiched between the other end 43 from the vertical direction.

  In the above-described embodiment, the case where a wire having a relatively large diameter is used as the lead wire 32 has been described. However, it is an exciting coil that receives a small current supplied from the control device, and the lead wire is a thin wire. You may apply to. In that case, the lead wire is wound around the other end 43 and then soldered. If the other end 43 has a circular cross section, the lead wire is loosened before soldering or the like. If 43a is formed, the lead wire is prevented from loosening due to the action of the edge portion of the connecting portion 43a.

  In addition, this invention is not limited to an above-described form, You may add a various change in the range which does not deviate from the summary of this invention.

The figure which shows the structure of one embodiment of this invention II-II sectional view Enlarged view of part III Modified example of the other end of the electrode

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electromagnetic safety valve 2 Fixed iron core 3 Excitation coil 4 Electrode 5 O-ring 31 Bobbin 32 Lead wire 43 (electrode) other end 43a Connection part

Claims (3)

It has a U-shaped fixed iron core housed in a metal holder member and a bobbin attached to at least one of the magnetic poles of the fixed iron core and wound with an exciting coil, and one end penetrates the holder member When the exciting coil is energized through an electrode that is exposed to the outside and the other end is not exposed to the outside of the electromagnetic safety valve , the movable core is attracted and held by the fixed core, and the valve body connected to the movable core is opened. In an electromagnetic safety valve held in a valve state, a non-hollow round bar electrode is bent into an L shape, the electrode is held on the bobbin so that the bent portion is buried in the bobbin, and the other end of the electrode is exposed from the bobbin. In order to form a connecting portion to which the lead wire drawn from the exciting coil is connected to the other end, and to attach a seal member between the round bar electrode and the holder member, the cross section of this electrode shape is circular Mano provided seal mounting portion, between the one end side of the electrode exposed to the outside through the connection portion and the holder member located within the electromagnetic safety valve by mounting an annular sealing member to the seal mounting portion An electromagnetic safety valve characterized by sealing at points.   The electromagnetic safety valve according to claim 1, wherein an external thermocouple is connected to the exciting coil, and the connecting portion is formed in a substantially flat shape. The electromagnetic safety valve according to claim 2, wherein the connecting portion is bent along the extending direction of the lead wire.

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