JP2005113991A - Electromagnetic valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic valve capable of easily assembling and being compact in size. <P>SOLUTION: The electromagnetic valve 10 comprises a solenoid coil 16 formed by winding a winding wire 20 on an outer periphery of a hollow bobbin 18 having a center hole 22 along a central axis 14, a fixed iron-core 46 fixed on an end in the center hole 22 of the hollow bobbin 18, a movable iron-core 50 moving toward the central axis 14 against the fixed iron-core 46, a valve body 36 opening and shutting a port 28 for fluid by connecting with the movable iron-core 50 and by moving the movable iron-core 50, and a frame 40 therein retaining the solenoid valve 16 and forming a magnetic path of the solenoid coil 16. The frame 40 is formed in an approximately rectangular shape in section by bending a sheet of a strip plate into an L-shape at four places in its longitudinal direction, and tip faces of both ends in a longitudinal direction of the plate are opposed with each other at a distance of a very small gap. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electromagnetic valve that is mounted in a fluid circuit and performs switching or opening / closing of a fluid flow path.

  In a fluid circuit, a solenoid valve is often used to switch or open / close a fluid flow path. For example, a solenoid valve is also used as a pilot valve for a four-way switching valve.

  Such a solenoid valve includes a solenoid coil formed by winding a winding around the outer periphery of a hollow bobbin having a center hole along a center axis, and a fixed iron core fixed to one end of the center hole of the hollow bobbin. The movable iron core is slidably accommodated in the central hole of the hollow bobbin, the valve body is connected to the movable iron core to open and close the fluid port, and the frame holds the solenoid coil therein. The frame is generally formed from a ferromagnetic material and provides a magnetic path for the solenoid coil.

  Conventionally, this frame has a box shape composed of a cup-shaped portion and a lid portion in order to minimize the magnetic flux loss of the solenoid coil, and after inserting the solenoid coil into the cup-shaped portion, the cup It was manufactured by attaching a lid part to the opening part of the shape part and joining the edge part of the opening part of the cup-shaped part and the lid part by an appropriate method. However, such a box-shaped frame has a problem of increasing the number of parts and the number of manufacturing steps. In order to solve this problem, as described in Patent Document 1, in recent years, a frame is formed in a C-shaped cross section, a solenoid coil is inserted between both side plates of the frame, and a hollow bobbin is connected to its central axis. A method of assembling the coil portion by sandwiching in the direction has been adopted.

Japanese Patent Laid-Open No. 9-14480

  However, such a C-shaped frame reduces the number of steps, but reduces the magnetic path and increases the loss of magnetic flux. For this reason, in order to obtain the same output as a box-shaped frame, it is necessary to increase the thickness of the frame or increase the number of windings. This led to an increase in manufacturing costs.

Accordingly, an object of the present invention is to provide an electromagnetic valve that solves the above-described problems of the prior art, is easy to assemble, and can be reduced in size.
Another object of the present invention is to provide a solenoid valve capable of reducing the manufacturing cost while maintaining the output.

  In view of the above-described object, the present invention provides a solenoid coil formed by winding a winding around an outer periphery of a hollow bobbin having a center hole along a center axis, and is fixed to one end portion in the center hole of the hollow bobbin. A fixed iron core, a movable iron core that moves in the direction of the central axis relative to the fixed iron core, a valve body that is connected to the movable iron core and opens and closes a fluid port by the movement of the movable iron core, and the solenoid coil therein. An electromagnetic valve comprising a frame that holds and forms a magnetic path of the solenoid coil, wherein the frame is in contact with one end portion in the central axis direction of the hollow bobbin, and both sides of the central axis line of the hollow bobbin A pair of side plate portions that extend so as to face each other and are integrally coupled to the end plate portion at one end portion, respectively, from the other end portion of each side plate portion toward the central axis. A pair of extending portions extending from each other, the tip surfaces of the extending portions facing each other with a slight gap, and the solenoid between the pair of extending portions and the end plate portion. An electromagnetic valve for sandwiching a coil is provided.

  In the electromagnetic valve, by providing an extension portion on the frame, the magnetic flux loss is improved and the output of the solenoid coil is improved as compared with a conventional frame having a C-shaped cross section. Furthermore, since the gap is formed between the tip surfaces of the pair of extension portions, the processing accuracy of the frame can be easily managed as compared with the case where the tip surfaces are completely brought into contact with each other. Further, by reducing this gap, the magnetic flux loss is kept small. On the other hand, the frame is formed as a single part, and the solenoid coil can be easily inserted into the frame from the side of the frame by widening the space between the front end surfaces of the extension. The assembly process is not increased as compared with the case.

  In the electromagnetic valve, it is preferable that the frame is formed to have a substantially rectangular cross section by bending a single belt-like plate into an L shape at four points in the longitudinal direction. When forming a frame in this way, the frame can be easily manufactured from a belt-like plate by press molding.

  In the electromagnetic valve, the slight gap is preferably 1 mm or less. By setting the gap to such a size, magnetic flux loss due to the provision of the gap can be kept low.

  Furthermore, in the solenoid valve, it is preferable that the extension portion is inclined and extends toward the end plate portion. In this case, since the extension portion is provided with a spring property, the solenoid coil is sandwiched between the pair of extension portions and the end plate portion in response to a minute change in the length dimension of the hollow bobbin in the central axis direction. Can be fixed.

  According to the electromagnetic valve of the present invention, the magnetic flux loss is improved as compared with a conventional frame having a C-shaped cross section, so that the electromagnetic valve can be miniaturized. Further, since the assembly is easy and the number of processes is not increased, the manufacturing cost is not increased.

  FIG. 1 shows an electromagnetic valve 10 used as a pilot valve for operating a main valve of a four-way switching valve as one embodiment of the present invention. The solenoid valve 10 includes a cylindrical solenoid tube 12 having a center axis 14 and a solenoid formed by winding a winding 20 around the outer periphery of a hollow bobbin 18 having a center hole 22 along the center axis 14. A coil 16.

  One end of the solenoid tube 12 is inserted and fixed in the center hole 22 of the hollow bobbin 18 of the solenoid coil 16. On the other hand, an end cap 13 is attached to the other end portion of the solenoid tube 12, and a cylindrical valve chamber 24 is formed inside the other end side portion. A flat valve seat 26 in which three fluid ports 28 are formed in a row in the direction of the central axis 14 of the solenoid tube 12 is provided on the peripheral wall of the valve chamber 24. A thin tube 30 communicating with each fluid port of a main valve (not shown) is connected. In addition to the three fluid ports 28, an additional port 32 is formed in the end cap 13, and a thin tube 34 communicating with one of the fluid ports of the main valve is also connected to the additional port 32. Yes. In the embodiment shown in FIG. 1, the valve seat 26 is formed by a valve seat block inserted into a hole formed in the peripheral wall of the valve chamber 24 and having three ports.

  The valve chamber 24 accommodates a valve body 36 having a recess 38 on a contact surface that contacts the valve seat 26, and the valve body 36 slides on the valve seat 26 in the direction of the central axis 14 of the solenoid tube 12. In motion, the recess 38 selectively communicates two adjacent two of the three fluid ports 28.

  The solenoid coil 16 is made of a magnetic material and is held inside a frame 40 that forms a magnetic path. The solenoid tube 12 passes through an opening 42 formed in the frame 40 in the center hole 22 of the hollow bobbin 18. Has been inserted.

  A cylindrical fixed iron core 46 is disposed at the end of the solenoid tube 12 near the hollow bobbin 18, and is fixed to the frame 40 by screws 48 extending through the frame 40. A cylindrical movable iron core 50 is accommodated in the solenoid tube 12 so as to be opposed to the fixed iron core 46 and slidable in the direction of the central axis 14.

  A shading ring 52 is attached to the end surface of the fixed iron core 46 near the movable iron core 50 in order to reduce the adverse effect of the alternating magnetic field generated in the solenoid coil 16 on the fixed iron core 46. Further, an urging spring 54 is disposed between the fixed iron core 46 and the movable iron core 50, and urges the movable iron core 50 in a direction to be separated from the fixed iron core 46.

  On the other hand, a valve body 36 is attached to the end of the movable core 50 on the side close to the valve seat 26 via a “fly-back” shaped valve body holder 56, and the valve body 36 is the center of the movable core 50. The valve seat 26 is slid by movement in the direction of the axis 14. In the embodiment shown in FIG. 1, the valve body holder 56 is fixed by caulking in the movable iron core 50 in the hole 58 extending in the direction of the central axis 14, and in the hole formed at the tip of the valve body holder 56. The valve body 36 is inserted, and the valve body 36 is pressed against the valve seat 26 by a leaf spring 62 attached to the valve body holder 56 by a rivet 60.

  Next, the frame 40 of the solenoid coil 16 of the solenoid valve shown in FIG. 1 will be described in detail with reference to FIGS.

  The frame 40 of the solenoid coil 16 shown in FIG. 1 is formed as a single part made of a magnetic material, and a pair of side plate portions arranged so as to face each other on both sides of the central axis 14 of the hollow bobbin 18. 64, an end plate portion 66 that extends between one end portions of the pair of side plate portions 64 and integrally couples them, and the other end portion of each side plate portion 64 toward the central axis 14 of the hollow bobbin 18, respectively. A pair of extending portions 68 extending from each other, and the tip surfaces of the pair of extending portions 68 face each other with a slight gap 70 therebetween. Further, as best seen in FIG. 3, the extension portion 68 extends in an inclined manner toward the end plate portion 66, and exhibits a spring property in the direction of the central axis 14. Furthermore, a relatively small-diameter screw hole 72 is formed in the center of the end plate portion 66 in order to pass a screw 48 for fixing the fixed iron core 46 to the frame 40. A semi-circular cutout 74 is provided in the center for passing the solenoid tube 12, and the two cutouts 74 form one relatively large diameter opening 42.

  Such a frame 40 is formed, for example, by press molding, by bending a single belt-shaped plate made of a magnetic material into an L shape along the widthwise folding line at four locations in the longitudinal direction so that the cross-section is substantially rectangular. Can be created. Of course, the frame 40 can also be produced by other methods such as casting.

  When assembling the solenoid coil 16 and the frame 40, one end in the direction of the central axis 14 of the hollow bobbin 18 is directed toward the end plate 66, and the other end in the direction of the central axis 14 of the hollow bobbin 18 is extended as a pair. The solenoid coil 16 is disposed on the side of the frame 40 toward the portion 68, and the solenoid coil 16 is inserted into the frame 40 in a state where the distal end surfaces of the pair of extension portions 68 are pushed away from each other. The solenoid coil 16 is pushed into the frame 40 to a position where one end portion in the direction of the central axis 14 of the hollow bobbin 18 comes into contact with the two protrusions 76 formed on the inner surface of the end plate portion 66 of the frame 40. It is sandwiched between the end plate portion 66 and the pair of extension portions 68. At this time, the solenoid coil 16 has the center of the screw hole 72 of the end plate portion 66 and the center of the opening portion 42 formed by the notch portions 72 of the pair of extension portions 68 on the central axis 14 of the hollow bobbin 18. It is arranged to be located.

  Unlike the conventional frame formed of a plurality of parts, the frame 40 does not require a step of joining the frame parts, but due to the presence of the extension 68, the magnetic path is compared with the conventional C-shaped frame. The magnetic flux loss of the solenoid coil 16 can be reduced. The decrease in the magnetic flux loss of the solenoid coil 16 increases the output of the solenoid coil 16, leading to a decrease in power consumption, a decrease in minimum operating voltage, and an increase in coil temperature. Therefore, when designing a solenoid coil having a predetermined output, the frame 40 shown in FIGS. 2 to 4 reduces the amount of the winding 20 used in the solenoid coil 16 and also in the direction of the central axis 14 of the hollow bobbin 18. The length is reduced, the manufacturing cost of the solenoid coil 16 is reduced, and the solenoid coil 16 is reduced in size.

  Further, the slight gap 70 provided between the extension portions 68 of the frame 40 pushes and opens the pair of side plate portions 64 and the pair of extension portions 68 away from each other so that the solenoid coil 16 can be easily moved into the frame 40. Makes it possible to insert into On the other hand, since the frame 40 forms the magnetic path of the solenoid coil 16, the magnetic flux loss of the solenoid coil 16 is increased when the gap 70 between the end faces of the extension portion 68 is increased. Therefore, the gap 70 is preferably formed to be 0.5 mm or less when the frame 40 is press-molded, and is preferably 1 mm or less after the solenoid coil 16 is inserted into the frame 40.

  Although the present invention has been described with reference to the embodiment shown in the accompanying drawings, this embodiment is merely illustrative and not restrictive. In addition, since the scope of the present invention is limited by the scope of the claims, the above-described embodiments can be modified and changed without departing from the scope of the claims. For example, the electromagnetic valve 10 shown in FIG. 1 is of a so-called bodyless type in which a valve chamber 24 is formed in the solenoid tube 12, but the present invention is as shown in FIG. Further, the present invention can be applied to an electromagnetic valve 10 ′ of a type in which a valve housing 78 is attached to the end of the solenoid tube 12 located on the opposite side of the solenoid coil 16 and the valve chamber 24 is formed in the valve housing 78. . The electromagnetic valve 10 ′ shown in FIG. 5 has the same configuration as the electromagnetic valve 10 of FIG. 1 except that the valve chamber 24 is constituted by a valve housing 78, and will not be described in detail here. 1 and 5, the same reference numerals are used for corresponding parts.

1 is an overall configuration diagram of an embodiment of a solenoid valve according to the present invention. It is a perspective view which shows the flame | frame of the solenoid coil currently used with the solenoid valve of FIG. FIG. 3 is a side view of the frame of FIG. 2. FIG. 3 is a front view of the frame of FIG. 2. It is a whole block diagram of other embodiment of the solenoid valve by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Solenoid valve 12 ... Solenoid tube 13 ... End cap 14 ... Center axis 16 ... Solenoid coil 18 ... Hollow bobbin 20 ... Winding 22 ... Center hole 24 ... Valve chamber 26 ... Valve seat 28 ... Fluid port 30 ... Narrow tube 32 ... Addition Port 34 ... narrow tube 36 ... valve body 38 ... recess 40 ... frame 42 ... opening 44 ... guide tube 46 ... fixed iron core 48 ... screw 50 ... movable iron core 52 ... shading ring 54 ... biasing spring 56 ... valve body holder 58 ... hole 60 ... Rivet 62 ... Leaf spring 64 ... Side plate portion 66 ... End plate portion 68 ... Extension 70 ... Gap 72 ... Screw hole 74 ... Notch 76 ... Projection 78 ... Valve housing

Claims (4)

A solenoid coil formed by winding a winding around the outer periphery of a hollow bobbin having a center hole along the center axis;
A fixed iron core fixed to one end in the center hole of the hollow bobbin;
A movable iron core that moves in the direction of the central axis relative to the fixed iron core;
A valve body connected to the movable core and opening and closing a fluid port by movement of the movable core;
In a solenoid valve comprising a frame that holds the solenoid coil inside and forms a magnetic path of the solenoid coil,
The frame extends so as to face each other on both sides of the central axis of the hollow bobbin, and is integrated with the end plate at one end of the hollow bobbin. It is formed as one part having a pair of side plate portions connected to each other and a pair of extension portions extending from the other end portion of each side plate portion toward the central axis, and the tip surfaces of the extension portions are separated by a slight gap. A solenoid valve that faces each other and sandwiches the solenoid coil between the pair of extension portions and the end plate portion.   2. The solenoid valve according to claim 1, wherein the frame is formed to have a substantially rectangular cross section by bending a single belt-like plate into an L shape at four locations in the longitudinal direction.   The solenoid valve according to claim 1, wherein the slight gap is 1 mm or less.   The electromagnetic valve according to claim 1, wherein the extension portion is inclined and extends toward the end plate portion.

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