JP2013155762A - Solenoid valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the noise generated when changing a solenoid valve using an electromagnetic coil having a fixed iron core.SOLUTION: A valve port 118 is opened/closed by pulling a movable iron core 108 by an electromagnetic coil 102 having a fixed iron core 106. A helical spring part 110 for urging the movable iron core 108 in the projecting direction from the electromagnetic coil 102 is provided. The spring constant of the helical spring part 110 is set so as to be increased when the movable iron core 108 is attracted and pressed in the electromagnetic coil 102. In this condition, the movable iron core 108 to be attracted into the electromagnetic coil 102 is subjected to a large reaction force from the helical spring part 110 from the stage when the movable iron core 108 is collided with the fixed iron core 106, and its moving speed is reduced, and the collision speed to the fixed iron core 106 is controlled. Thus, generation of loud noise when changing a solenoid valve 10 can be avoided.

Description

  The present invention relates to a solenoid valve used for a gas appliance or the like.

  In various gas appliances such as water heaters and gas stoves, solenoid valves are widely used for the purpose of controlling the flow of fluids such as fuel gas, water, and hot water. This solenoid valve has an operation principle of opening and closing a valve opening by moving a movable iron core (plunger) connected to a valve body with an electromagnetic coil. Also, in order to efficiently guide the magnetic flux generated in the electromagnetic coil to the movable iron core so that the movable iron core can be moved, a fixed iron core (core) made of a material with high magnetic permeability is also provided at the center of the electromagnetic coil. Has been done.

  For example, Patent Document 1 discloses a direct-acting electromagnetic valve in which a fixed iron core is provided in an electromagnetic coil. Patent Document 2 discloses a pilot-type solenoid valve, and Patent Document 3 discloses a self-holding solenoid valve. In these solenoid valves, since the magnetic flux of the electromagnetic coil is efficiently transmitted to the movable iron core by the fixed iron core, the movable iron core can be attracted with a strong force, and the switching operation of the solenoid valve can be performed quickly.

JP 2010-114151 A JP 2000-169404 A Japanese Patent Laid-Open No. 9-159045

  However, the solenoid valve provided with the fixed iron core in the electromagnetic coil has a problem that the movable iron core may be vigorously collided with the fixed iron core and generate a loud sound as a result of the movable iron core being attracted by a strong force.

  The present invention has been made in response to the above-mentioned problems of the prior art, and can generate a loud sound at the time of switching while being able to perform a quick switching operation by using an electromagnetic coil having a fixed iron core. The purpose is to provide a solenoid valve without any problems.

In order to solve the above-described problems, the solenoid valve of the present invention employs the following configuration. That is,
An electromagnetic coil formed into a cylindrical shape by winding an electric wire, a fixed iron core inserted along the central axis of the electromagnetic coil from one end side of the electromagnetic coil, and the central axis from the other end side of the electromagnetic coil Between the movable iron core slidably inserted in the coil, a coiled spring portion that urges the movable iron core in a direction to project from the electromagnetic coil, a valve body connected to the movable iron core, and the valve body A solenoid valve comprising a valve seat forming a valve opening,
The string-wound spring portion is characterized in that when the movable iron core is compressed by being drawn into the electromagnetic coil, a spring constant of the string-wound spring portion is increased.

  In such a solenoid valve of the present invention, when the electromagnetic coil is not energized, the coiled spring portion urges the movable iron core in the direction in which the movable iron core protrudes from the electromagnetic coil. Be drawn into. As a result, the valve body connected to the movable iron core moves, and the valve opening is switched between the open state (valve open state) and the closed state (valve closed state). The direction in which the string spring portion urges the movable iron core can be either the direction of closing the valve port or the direction of opening the valve port. Since the fixed iron core is inserted in the electromagnetic coil, the movable iron core is drawn into the electromagnetic coil with a strong force, and as a result, the valve open state and the valve closed state can be quickly switched. Here, when the movable iron core is drawn into the electromagnetic coil and compressed, the spring constant of the string-wound spring portion urging the movable iron core in the direction in which the movable iron core protrudes from the electromagnetic coil increases. The mode in which the spring constant increases may increase suddenly when the movable iron core moves to some extent, or may gradually increase with the movement of the movable iron core. In addition, the string spring portion may be provided so as to be compressed when the movable iron core is drawn into the electromagnetic coil. Therefore, the string winding spring portion may be provided between the fixed iron core and the movable iron core in the electromagnetic coil. It can also be provided outside the coil.

  In this way, the movable core drawn into the electromagnetic coil approaches the fixed core while receiving a large reaction force from the chord spring part from the stage before colliding with the fixed core, so the movable core collides with the fixed core. In the meantime, the moving speed of the movable iron core is gradually reduced. As a result, it is possible to prevent the movable iron core from colliding with the fixed iron core at a high speed, and it is possible to avoid the generation of a loud sound when the electromagnetic valve is switched.

  In the electromagnetic valve of the present invention described above, a string-wound spring (biasing spring) that urges the movable iron core in a direction to protrude from the electromagnetic coil, and a string-wound spring (braking spring) that has a shorter spring length than the urging spring; When the movable iron core is drawn into the electromagnetic coil, the spring constant may be increased from the uncompressed state to the compressed state.

  If it carries out like this, from the stage in which a movable iron core approached to a fixed iron core to some extent, the reaction force of a braking spring will also act on a movable iron core, and a movable iron core can be decelerated. For this reason, it is possible to prevent the movable iron core from colliding with the fixed iron core at a high speed, and to avoid generating a loud sound when switching the electromagnetic valve.

  Moreover, in the electromagnetic valve of the present invention described above, the string winding having the densely wound portion in which the spring element is wound at the first pitch and the coarsely wound portion wound at the second pitch longer than the first pitch. The string-wound spring portion may be constituted by a spring.

  In this way, when the movable iron core is drawn into the electromagnetic coil, the close winding portion of the string winding spring is in close contact with the spring element wire, but the coarse winding portion is not in close contact, and the substantial number of turns of the string winding spring. Decrease. Here, since the spring constant of the string-wound spring is inversely proportional to the number of turns, the spring constant increases as the substantial number of turns decreases. As a result, since the moving speed is decelerated before the movable iron core collides with the fixed iron core, it is possible to avoid the generation of a loud sound when the electromagnetic valve is switched. In this case, since the string-wound spring portion can be constituted by one string-wound spring, the structure of the electromagnetic valve is simplified, and the electromagnetic valve can be miniaturized.

  Moreover, in the electromagnetic valve of this invention mentioned above, you may comprise a string winding spring part as follows. First, the first spring and the second spring are provided in series with respect to the moving direction of the movable iron core. The first spring is a string-wound spring that comes into close contact before the movable iron core reaches the fixed iron core when the movable iron core is drawn into the electromagnetic coil and compressed. Further, the second spring is a string-wound spring that does not come into close contact even when the movable iron core is drawn into the electromagnetic coil and compressed. In addition, as such a 1st spring and a 2nd spring, the coiled spring from which a spring pitch differs can be prepared, for example, the one with a short spring pitch can be made into a 1st spring, and the one with a long spring pitch can be made into a 2nd spring. Alternatively, a string spring having different spring constants may be prepared, and the smaller spring constant (soft spring) may be used as the first spring, and the larger spring constant (hard spring) may be used as the second spring.

  For example, when string wound springs having different spring pitches are used as the first spring and the second spring, the first spring is brought into a close contact state when the movable iron core is pulled into the electromagnetic coil to some extent. And the total number of turns of the second spring) decreases. For this reason, when the movable iron core is drawn into the electromagnetic coil and compressed, it is possible to realize a string-wound spring portion having a large spring constant. Alternatively, when string-wound springs having different spring constants are used as the first spring and the second spring, the first spring having a small spring constant is mainly deformed at first, but the movable iron core is drawn to the electromagnetic coil to some extent. After the first spring comes into close contact, the second spring is deformed. Accordingly, even in this case, it is possible to realize a string-wound spring portion in which the spring constant increases when the movable iron core is drawn into the electromagnetic coil. As a result, since the moving speed of the movable core is reduced before the movable core collides with the fixed core, it is possible to avoid the generation of a loud sound when the solenoid valve is switched. In this way, for each of the first spring and the second spring, a normal string-wound spring whose spring pitch does not change can be used. Since a normal string spring is easily available and can be obtained at a low cost, the electromagnetic valve can be easily manufactured.

It is sectional drawing which shows operation | movement of the solenoid valve 10 of a present Example. It is explanatory drawing which shows the reason which the solenoid valve 10 of a present Example can suppress a collision sound. It is sectional drawing which shows the structure of the solenoid valve 20 of a 1st modification. It is explanatory drawing which shows operation | movement of the solenoid valve 20 of a 1st modification. It is sectional drawing which shows the structure of the solenoid valve 30 of a 2nd modification.

  FIG. 1 is a cross-sectional view showing the operation of the electromagnetic valve 10 of this embodiment. FIG. 1A shows the electromagnetic valve 10 in a closed state, and FIG. 1B shows the electromagnetic valve 10 in an opened state. In the following, a direct acting type solenoid valve that is opened by energization will be described as an example. However, the solenoid valve is not limited to such a solenoid valve. Furthermore, the present invention can also be applied to various types of electromagnetic valves such as electromagnetic valves that are closed by energization.

  As shown in FIG. 1, the electromagnetic valve 10 of the present embodiment includes a cylindrical electromagnetic coil 102 formed by winding an electric wire, a guide pipe 104 inserted on the central axis of the electromagnetic coil 102, a guide A cylindrical fixed iron core 106 fitted from one end side of the pipe 104, a movable iron core 108 slidably inserted from the other end side of the guide pipe 104, and the fixed iron core 106 and the movable iron core 108 are provided. A long string-wound spring (biasing spring 110), a short string-wound spring (braking spring 112) provided inside the biasing spring 110, and the distal end side of the movable iron core 108 (opposite to the side inserted into the guide pipe 104) And a valve seat 116 forming a valve port 118 between the valve body 114 and the like.

  In a state where the electromagnetic coil is not energized, the valve body 114 is pressed against the valve seat 116 by the force by which the biasing spring 110 biases the movable iron core 108, and the valve port 118 is closed (valve closed state). (See FIG. 1 (a)). Further, since the spring length of the brake spring 112 is shorter than that of the urging spring 110, the brake spring 112 is not in contact with the fixed iron core 106 when the valve is closed. In the example shown in FIG. 1, the brake spring 112 is attached to the movable iron core 108, but may be attached to the fixed iron core 106. In the present embodiment, the spring system constituted by the two string wound springs of the biasing spring 110 and the brake spring 112 corresponds to the “string wound spring portion” in the present invention.

  When the electromagnetic coil 102 is energized, the magnetic force generated by the electromagnetic coil 102 overcomes the force of the biasing spring 110, and the movable iron core 108 is drawn into the guide pipe 104. As a result, as shown in FIG. 1B, the valve body 114 formed on the end surface of the movable iron core 108 is separated from the valve seat 116 and the valve port 118 is opened (opened state). Fluid (fuel gas, water, hot water, etc.) flows as shown by the thick dashed arrows. Further, in the valve open state, not only the biasing spring 110 is compressed, but also the braking spring 112 is compressed. By doing in this way, it becomes possible to avoid that a big collision sound is generated at the time of valve opening for the following reasons.

  In FIG. 1B, the movable iron core 108 is in contact with the fixed iron core 106 in the valve open state, but the movable iron core 108 is not necessarily in contact with the fixed iron core 106. For example, the reaction force received from the urging spring 110 and the braking spring 112 without the movable iron core 108 coming into contact with the fixed iron core 106 is balanced with the magnetic force that the electromagnetic coil 102 attracts the movable iron core 108, so that the movable iron core 108 is fixed to the fixed iron core 106. You may make it stabilize in the state away from 106. FIG. Of course, a buffer member such as a rubber sheet may be provided on one of the movable core 108 and the fixed core 106 so that the movable core 108 and the fixed core 106 are in contact with each other via the buffer member.

  FIG. 2 is an explanatory diagram showing the reason why the electromagnetic valve 10 of this embodiment can suppress the collision sound. FIG. 2 shows a spring system (the biasing spring 110 and the braking spring) until the movable core 108 moves from the valve-closed state (see FIG. 1A) to the valve-opened state (see FIG. 1B). 112) and the change in the reaction force (spring reaction force) that the movable iron core 108 receives from the spring system are conceptually shown. As shown in FIG. 1A, the braking spring 112 is not in contact with the fixed iron core 106 in the valve closed state. For this reason, immediately after the start of movement from the valve-closed state, the movable iron core 108 receives a reaction force from only the urging spring 110, and the spring constant of the spring system is the spring constant of the urging spring 110. As a result, the spring reaction force received by the movable iron core 108 gradually increases at a ratio corresponding to the spring constant of the biasing spring 110 as the movable iron core 108 moves. On the other hand, the movable iron core 108 is attracted with a strong force by the effect of the fixed iron core 106. For this reason, the moving speed of the movable iron core 108 increases by overcoming the spring reaction force of the biasing spring 110.

  However, as the movable iron core 108 moves, the brake spring 112 eventually comes into contact with the fixed iron core 106, and thereafter, the spring reaction force of the brake spring 112 also acts on the movable iron core 108. For this reason, the spring constant as the spring system increases to a value obtained by adding the spring constant of the braking spring 112 to the spring constant of the biasing spring 110. As a result, as the movable iron core 108 moves, the spring reaction force received by the movable iron core 108 suddenly increases, and before the movable iron core 108 reaches the valve open position (the electromagnetic valve 10 is in the valve open state). The spring reaction force exceeds the magnetic force and the moving speed of the movable iron core 108 turns to deceleration. For this reason, since the speed at which the movable iron core 108 collides with the fixed iron core 106 is suppressed, it is possible to avoid the generation of a loud sound when the electromagnetic valve 10 is opened.

  In particular, in the electromagnetic valve 10 of the present embodiment, the brake spring 112 is constituted by a string spring as is the urging spring 110. For this reason, since the stroke of the braking spring 112 can be taken sufficiently, the braking spring 112 is brought into contact with the fixed iron core 106 from a stage before the movable iron core 108 collides with the fixed iron core 106, so that the braking spring 112 A spring reaction force can be applied to the movable iron core 108. For example, in the example shown in FIGS. 1 and 2, the brake spring 112 is in contact with the fixed iron core 106 when the movable iron core 108 has moved about half of the distance moved when the valve is opened. For this reason, since the moving speed of the movable core 108 can be sufficiently decelerated until it collides with the fixed core 106, it is possible to more reliably suppress the generation of a loud noise when the solenoid valve 10 is opened. It becomes possible. Further, if the spring constant of the braking spring 112 is set to a value larger than the spring constant of the biasing spring 110, the moving speed of the movable iron core 108 can be further sufficiently reduced. Sound generated when the valve is opened can be further suppressed.

  In addition, the use of a string-wound spring as the braking spring 112 has the following advantages. That is, the stroke of the braking spring 112 can be sufficiently taken between the time when the braking spring 112 comes into contact with the fixed core 106 and the time when the movable core 108 collides with the fixed core 106. 108 receives a sufficient reaction force from the brake spring 112, but initially, the spring reaction force received from the brake spring 112 can be reduced. For this reason, when the braking spring 112 collides with the fixed iron core 106, there is no possibility that a loud sound will be generated because a large spring reaction force is generated in an impact.

  Further, if the end face of the brake spring 112 (particularly, the end face on the side in contact with the fixed core 106) is formed flat by polishing or the like, the brake spring 112 strikes the fixed core 106 and is obliquely directed to the movable core 108. The power of is not added. For this reason, since the movable iron core 108 does not move in the guide pipe 104, the movable iron core 108 slides smoothly, and the movable iron core 108 or the guide pipe 104 is worn by long-term use. This can also be avoided.

  In addition, since the movable iron core 108 is decelerated using the brake spring 112, even when used for a long period of time, the cushion performance is reduced as in the case of using a cushion material such as sponge or rubber member. There is nothing. As a result, even when the electromagnetic valve 10 is used for a long period of time, it is possible to suppress the generation of a loud sound when the valve is opened. Furthermore, since the brake spring 112 is provided inside the biasing spring 110, there is no possibility that the solenoid valve 10 will be enlarged by providing the brake spring 112.

  Several modifications can be considered for the electromagnetic valve 10 of the present embodiment described above. Hereinafter, these modified examples will be briefly described.

  In the above-described embodiments, the spring system that generates the reaction force in the movable iron core 108 has been described as being constituted by separate string-wound springs (the biasing spring 110 and the braking spring 112). However, they can also be a single string spring.

  FIG. 3 is a cross-sectional view showing the structure of the electromagnetic valve 20 of the first modified example. As shown in the drawing, in the solenoid valve 20 of the first modified example, only the urging spring 210 that is one chord spring is provided between the fixed iron core 106 and the movable iron core 108. Instead, the urging spring 210 is a so-called unequal pitch spring, and is provided with a closely wound portion 210a around which a spring element wire is wound at a small spring pitch and a coarsely wound portion 210b wound at a large spring pitch. ing. If such an urging spring 210 is used, the function of the urging spring 110 and the function of the braking spring 112 can be realized by one urging spring 210 as follows. In the first modification, the urging spring 210 corresponds to the “string spring portion” in the present invention.

  FIG. 4 is an explanatory diagram showing the operation of the urging spring 210 in the first modification. In FIG. 4, the portion of the biasing spring 210 is shown enlarged. When the solenoid valve 20 is in the closed state, as shown in FIG. 4A, the biasing spring 210 is not in close contact with the spring element wire in either the densely wound portion 210a or the coarsely wound portion 210b. When the movable iron core 108 moves in this state, the entire biasing spring 210 (the closely wound portion 210a and the coarsely wound portion 210b) is compressed in the same manner. However, since the closely wound portion 210a has a small spring pitch, the spring wire of the closely wound portion 210a is in close contact with each other as shown in FIG. 4B. Thereafter, only the urging spring 210 of the coarsely wound portion 210b is compressed. FIG. 4C shows a state where the electromagnetic valve 20 is finally opened.

  Thus, in the solenoid valve 20 of the first modified example, while the spring element wire of the densely wound portion 210a is not in close contact, the entire biasing spring 210 is a string wound spring. When the wire is in close contact, only the portion of the coarsely wound portion 210b of the biasing spring 210 becomes a substantial string wound spring. The spring constant of the string wound spring is inversely proportional to the number of turns of the spring wire. Therefore, when the closely wound portion 210a is in close contact, the substantial spring constant of the biasing spring 210 increases. In the example of FIG. 4, the total number of turns of the urging spring 210 is 9, whereas the number of turns of the coarse winding part 210 b is 3, so the spring constant increases three times. As described above, in the electromagnetic valve 20 of the first modified example, when the tightly wound portion 210a of the urging spring 210 is brought into close contact with the valve during opening, the spring constant increases and the moving speed of the movable core 108 is reduced. It is possible to avoid the generation of a loud sound by suppressing the speed of collision with the fixed iron core 106.

  In the first modification described above, the biasing spring 210 is described as an unequal pitch spring. However, it is not necessary to use unequal pitch springs as follows.

  FIG. 5 is a cross-sectional view showing the structure of the electromagnetic valve 30 of the second modified example. As shown in the drawing, in the electromagnetic valve 30 of the second modification, a first spring 312 that is a string-wound spring having a small spring pitch, a second spring 316 that is a string-wound spring having a larger spring pitch than the first spring 312, A biasing spring system 310 is configured by a spacer 314 provided between the spring 312 and the second spring 316. In the second modification, the biasing spring system 310 corresponds to the “string winding spring portion” of the present invention.

  For convenience of explanation, it is assumed that the spring wire of the first spring 312 and the spring wire of the second spring 316 have the same wire diameter and material. Then, the first spring 312 of the second modified example corresponds to the densely wound portion 210a of the first modified example, and the second spring 316 of the second modified example corresponds to the coarsely wound portion 210b of the first modified example. Thus, the biasing spring system 310 of the second modification acts exactly the same as the biasing spring 210 of the first modification. As a result, as in the first modification described above, the speed at which the movable iron core 108 collides with the fixed iron core 106 when the valve is opened is suppressed, so that it is possible to avoid the generation of a loud sound.

  In the second modification, the first spring 312 and the second spring 316 do not necessarily have to be formed of the same wire diameter and the same spring element wire. Furthermore, if the wire diameter or material of the spring wire is made different, it is no longer necessary to make the spring pitch different between the first spring 312 and the second spring 316. For example, the first spring 312 is formed from a thin spring wire, and the second spring 316 is formed from a thick spring wire. Then, the first spring 312 is soft (the spring constant is small) and the second spring 316 is hard (the spring constant is large), so the first spring 312 is mainly compressed initially. Then, after the first spring 312 comes into close contact, the second spring 316 is compressed. For this reason, since the spring constant increases in the middle of the valve opening operation, the speed at which the movable iron core 108 collides with the fixed iron core 106 at the time of valve opening is suppressed as in the first modified example described above. It is possible to avoid the occurrence.

  In addition, in the second modification of any aspect described above, the first spring 312 and the second spring 316 can be separated, so that each of the first spring 312 and the second spring 316 is A general string spring having a constant spring pitch can be used. For this reason, it becomes possible to manufacture the solenoid valve 30 at low cost.

  The electromagnetic valves 10, 20, and 30 of the present embodiment and various modifications have been described above. However, the present invention is not limited to the above-described embodiment, and may be implemented in various modes without departing from the spirit of the present invention. Is possible. For example, the electromagnetic valves 10, 20, and 30 of the present embodiment and the various modifications described above are all direct acting, and are described as electromagnetic valves that are opened by energizing the electromagnetic coil 102. However, it may be a pilot type, a self-holding type, or an electromagnetic valve that closes when energized.

10 ... Solenoid valve, 20 ... Solenoid valve, 30 ... Solenoid valve,
102 ... Electromagnetic coil, 104 ... Guide pipe, 106 ... Fixed iron core,
108 ... movable iron core, 110 ... biasing spring, 112 ... brake spring,
114 ... Valve, 116 ... Valve seat, 118 ... Valve,
210 ... Biasing spring, 210a ... Dense winding part, 210b ... Rough winding part 310 ... Biasing spring system, 312 ... First spring, 314 ... Spacer,
316 ... second spring

Claims (4)

An electromagnetic coil formed into a cylindrical shape by winding an electric wire, a fixed iron core inserted along the central axis of the electromagnetic coil from one end side of the electromagnetic coil, and the central axis from the other end side of the electromagnetic coil Between the movable iron core slidably inserted in the coil, a coiled spring portion that urges the movable iron core in a direction to project from the electromagnetic coil, a valve body connected to the movable iron core, and the valve body A solenoid valve comprising a valve seat forming a valve opening,
The electromagnetic valve according to claim 1, wherein when the movable iron core is compressed by being drawn into the electromagnetic coil, a spring constant of the string winding spring portion is increased. The electromagnetic valve according to claim 1,
The string spring portion is
An urging spring that is a string-wound spring that urges the movable iron core in a direction to protrude from the electromagnetic coil, and a braking spring that is a string-wound spring having a shorter spring length than the urging spring;
When the movable iron core is drawn into the electromagnetic coil, the electromagnetic spring changes from an uncompressed state to a compressed state. The electromagnetic valve according to claim 1,
The string-wound spring part is a string-wound spring having a densely wound part in which a spring element is wound at a first pitch and a coarsely wound part wound at a second pitch longer than the first pitch. Characteristic solenoid valve. The electromagnetic valve according to claim 1,
The string spring portion includes a first spring and a second spring provided in series with respect to the first spring in the moving direction of the movable iron core,
The first spring is a string-wound spring that comes into close contact before the movable iron core reaches the fixed iron core when the movable iron core is drawn into the electromagnetic coil and compressed.
The solenoid valve according to claim 1, wherein the second spring is a coiled spring that does not come into close contact before the movable iron core reaches the fixed iron core even when the movable iron core is drawn into the electromagnetic coil and compressed.

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