JP2005061589A - Electromagnetic proportional valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic proportional valve that can assure an adjustment range of low flow widely by eliminating the dead band area. <P>SOLUTION: Beside rolling up a coil 11 on a coil bobbin 12 with a hollow hole and fixing a fixed core 13 to one opening end of the coil bobbin 12, a plunger 14 is inserted from another opening end of the coil bobbin 12 so as to be slidable, and a valve body 21 attached at the end of the plunger 14 is biased toward a valve seat 9 by the first spring 22 arranged between the fixed core 13 and the plunger 14. It is the electromagnetic proportional valve 1 that adjusts the flow of the fluid supplied from an input port 4 to an output port 5 by spacing the valve body 21 from the valve seat 9 according to the current value to the coil 11, and the valve seat 9 becomes free long when touching to the valve body 21 and the second spring 23 is fixed to the plunger 14 so as to leave the space h of a prescribed length to the sliding direction of the plunger 14. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electromagnetic proportional valve that adjusts a valve opening by balancing a spring load and a suction force of a coil.

  2. Description of the Related Art Conventionally, an electromagnetic proportional valve that adjusts a valve opening degree in proportion to a supply current amount is used for an apparatus that fills a container with a gas such as air, such as an industrial machine or a medical instrument. In these devices, a large flow rate is used to speed up the filling time of the container, and after filling, a small amount of fluid is filled to compensate for the pressure drop due to external leakage, etc. It is desired for the valve to accurately control a small flow rate and a large flow rate.

  As an example of an electromagnetic proportional valve, for example, one in which one spring is contracted between a fixed core and a plunger is known. The fixed core is loaded and fixed to one end of a coil bobbin around which a coil is wound, and a plunger is slidably inserted from the other end of the coil bobbin coaxially with the fixed core. A valve body is fixed to the lower end portion of the plunger, and a valve seat with which the valve body abuts or separates is disposed between the input port and the output port. A spring is contracted between the fixed core and the plunger, and a force in the valve seat direction is always applied to the valve body.

  As shown in L of FIG. 5, the electromagnetic proportional valve is proportional to the plunger stroke and the load acting as a reaction force of the suction force. Therefore, the plunger stroke (valve) is adjusted by adjusting the coil suction force. Opening degree) can be controlled. Since the attraction force of the coil is proportional to the current value, the flow of the plunger can be adjusted by controlling the plunger stroke by controlling the current value as shown in FIG.

  Here, since the electromagnetic proportional valve opens and closes the valve by sliding the plunger by the attractive force of the coil generated according to the current value to the coil, the stroke range of the plunger is narrow (for example, 1 mm or less) For example, as shown in FIG. 5, when a rated current value (see G1 in the figure) is supplied to the coil 11 and when a current value of 50% of the rated current value (see G4 in the figure) is supplied to the coil 11 , The former spring load is about five times the latter spring load. Therefore, it is necessary to use a spring having a large spring constant in order to accurately control the valve opening degree near the fully open position. However, when a spring having a large spring constant is used, the low flow rate adjustment range (see part C in FIG. 6) becomes extremely narrow, and fine flow rate adjustment is hardly possible within the low flow rate adjustment range. On the other hand, if the spring constant is reduced, the slope of the function of the spring load and displacement is reduced, so that the fine flow rate can be adjusted within the low flow rate adjustment range, but the flow rate cannot be adjusted with high accuracy near the fully open position. Therefore, in order to accurately perform the low flow rate adjustment and the large flow rate adjustment, it is necessary to provide two electromagnetic proportional valves.

  On the other hand, as shown in the sectional view of FIG. 7, it is conceivable to provide two springs 110 and 111 having different elastic pressures on the electromagnetic proportional valve 100. The electromagnetic proportional valve 100 includes a coil bobbin 102 around which a coil 101 is wound. A fixed core 103 is fixed to the upper end opening of the coil bobbin 102 in the drawing, and is coaxial with the fixed core 103 from the lower end opening of the coil bobbin 102 in the drawing. On top, a substantially cylindrical plunger 104 is slidably inserted. The plunger 104 has a through hole 104a formed in the axial direction, and a valve body 105 is attached so as to close the lower end opening in the figure. A valve seat 108 is provided coaxially with the valve body 105 between the input port 106 and the output port 107. A first spring 110 is contracted between the fixed core 103 and the plunger 104, and a force in the direction of the valve seat 108 is always applied to the valve body 105. A second spring 111 is inserted into the through-hole 104a of the plunger 104 so as to abut against the valve body 105 from the upper end opening in the figure, and is compressed and held by the piston 112. The second spring 111 is stronger in elastic force than the first spring 110 and is pressed and shrunk via the piston 112 by a convex portion 103 a protruding downward on the lower end surface of the fixed core 103.

  In the electromagnetic proportional valve 100, when a weak current is supplied to the coil 101, the plunger 104 rises while compressing the first spring 110, and the piston 112 eventually hits the convex portion 103 a of the fixed core 103. Since the second spring 111 has a larger elastic force than the first spring 110, the second spring 111 is not compressed even if the piston 112 abuts against the convex portion 103 a of the fixed core 103. Therefore, the plunger 104 stops at a position where the valve body 105 is slightly separated from the valve seat 108 and performs low flow rate adjustment. Thereafter, when the current supplied to the coil 101 is gradually increased, the attractive force of the coil 101 overcomes the elastic pressure of the second spring 111, and the plunger 104 compresses the first spring 110 and the second spring 112 while compressing them. Ascending, the valve body 105 is largely separated from the valve seat 108, and a large flow rate is adjusted. Therefore, the electromagnetic proportional valve 100 can perform a small flow rate adjustment and a large flow rate adjustment independently (see, for example, Patent Document 1).

JP-A-6-50459 (paragraphs 0005 to 0009, FIG. 1).

  However, in the conventional solenoid proportional valve 100, the second spring 111 is compressed and held in the through hole 104a of the plunger 104, and as shown by N2 in FIG. 8, the rated current value (100%: refer to H1 in the figure). On the other hand, it is not displaced until a current value of about 80% (see H2 in the figure) is supplied to the coil 101. In the electromagnetic proportional valve 100, for example, before a current value of 70% of the rated current value (see H3 in the figure) is supplied to the coil 101, the piston 112 abuts against the convex portion 103a of the fixed core 103. However, only the elastic force of the first spring 110 acts on the plunger 104, but when a current value of 70% or more with respect to the rated current value is supplied to the coil 101, the piston 112 comes into contact with the fixed core 103, and the plunger A load obtained by synthesizing the first spring 110 and the second spring 111 acts on 104 (see N3 in the figure). Therefore, even if the electromagnetic proportional valve 100 supplies a current value of 80% to the rated current value to the coil 101, the attractive force (see H2 in the figure) of the coil 101 is applied to the first spring 110 and the second spring. Even when the current value supplied to the coil 101 is increased from 70% to 80% of the rated current value, the plunger 104 is attracted to the fixed core 103 side, which is smaller than the load combined with 111 (see N3 in the figure). I can't. As described above, a gap is generated between the load (see N3 in the figure) obtained by combining the first spring 110 and the second spring 111 and the load on the first spring 110 (see N1 in the figure) (D in the figure). 9), as shown in FIG. 9, there was a dead zone Z in which the flow rate could not be adjusted linearly with respect to the current value. In addition, there is a problem that the low flow rate adjustment range X2 is narrowed by the amount of the dead zone Z.

  Accordingly, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide an electromagnetic proportional valve that can eliminate a dead zone region and can ensure a wide low flow rate adjustment range.

The electromagnetic proportional valve according to the present invention has the following configuration.
(1) A coil is wound around a coil bobbin having a hollow hole, a fixed core is fixed to one end opening of the coil bobbin, and a plunger is slidably inserted from the other end opening of the coil bobbin. A first elastic member (for example, a spring or the like) disposed therebetween urges the valve body attached to the tip of the plunger in the valve seat direction, and the plunger is moved according to the current value to the coil. In an electromagnetic proportional valve that adjusts the flow rate of the fluid supplied from the input port to the output port by separating the valve body from the valve seat, it is free length when the valve body is in contact with the valve seat, and the plunger slides It has the 2nd elastic member (for example, spring etc.) with which the clearance gap of a predetermined length is attached to a direction, and is mounted on a plunger.

(2) In the invention described in (1), the length of the gap is 10 to 20% of a stroke range in which the plunger moves from the fully closed position to the fully open position.

Next, the function and effect of the invention having the above configuration will be described.
In the invention having the configuration described in (1) above, when a weak current is supplied to the coil, the plunger slides against the elastic force of the first elastic member by the suction force of the coil, and the valve body is moved. Separate from the valve seat. Until the plunger slides by a gap of a predetermined length, the second elastic member remains in a free length and does not generate elastic pressure, and the reaction force against the suction force of the coil is small. If a current smaller than the current value necessary for sliding is supplied to the coil, the fluid supplied from the input port to the output port can be finely adjusted within the low flow rate adjustment range. Thereafter, when the current supplied to the coil is increased, the plunger slides by a gap of a predetermined length, and at the same time, the elastic member is compressed to start generating elastic pressure. Therefore, the plunger continues to slide against the first elastic member and the second elastic member without stopping, and adjusts the flow rate. Therefore, according to the present invention, it is possible to eliminate the dead zone and secure a wide low flow rate adjustment range.

  According to the invention having the configuration described in (2) above, in addition to the operational effects of the invention described in (1), the plunger slides toward the fixed core within a range of 10 to 20% of the stroke range from the fully closed position. When moving, only the elastic force of the first elastic member acts on the plunger to adjust the low flow rate, and when the plunger slides from the fully closed position to the fixed core side beyond the range of 10 to 20% of the stroke range, Since the combined force of the elastic pressure of the first elastic member and the elastic force of the second elastic member acts on the plunger to adjust the large flow rate, the low flow rate adjustment and the large flow rate adjustment can be performed independently.

Next, an embodiment of an electromagnetic proportional valve according to the present invention will be described with reference to the drawings. 1 and 2 are sectional views of the electromagnetic proportional valve 1.
The electromagnetic proportional valve 1 of the present embodiment is used in an apparatus for filling a container with a gas such as air, such as industrial machinery and medical machinery, and utilizes the difference in elastic pressure between the first and second springs 22 and 23. Thus, the gas fine flow rate adjustment and the large flow rate adjustment are performed independently.

  The electromagnetic proportional valve 1 includes a valve unit 2 that performs flow rate control and a driving unit 3 that applies a driving force to the valve unit 2. The valve portion 2 has a body 7 in which an input port 4 and an output port 5 are drilled in the horizontal direction in the drawing from the side, and a valve hole 6 is drilled in the vertical direction from the upper end surface in the drawing. A mounting hole 8 is formed coaxially with the valve hole 6 on the upper end surface of the body 7 in the figure, and a valve seat 9 is provided at an opening portion where the mounting hole 8 and the valve hole 6 communicate with each other. Therefore, the gas flowing into the input port 4 flows out from the output port 5 through the mounting hole 8, the valve seat 9 and the valve hole 6.

  On the other hand, the drive unit 3 includes a hollow cylindrical coil bobbin 12 around which the coil 11 is wound. The fixed core 13 is loaded and fixed in the upper end opening of the coil bobbin 12 in the figure, and the plunger 14 is slidably inserted from the lower end opening of the coil bobbin 12 in the figure. A plunger guide 15 is disposed between the coil bobbin 12 and the plunger 14 to ensure rigidity against sliding of the plunger 14. The wiring 16 is connected to the coil 11 and is taken out from the bush 17 to the outside. The fixed core 13 is caulked and fixed to the magnetic frame 18, and the bush 17 and the magnetic frame 18 are filled with resin to constitute a solenoid.

  The drive unit 3 is attached to the body 7 so that the plunger 14 is coaxial with the valve seat 9 of the valve unit 2. A seal member 19 such as an O-ring is disposed between the drive unit 3 and the body 7 to prevent fluid leakage. A lower end portion of the plunger 14 protrudes from the drive portion 2 to the valve portion 3, and a valve body 21 is attached to the lower end surface thereof. The valve body 21 is formed of an elastic body such as rubber or a resin such as PTFE having high heat resistance, and comes into airtight contact with the valve seat 9. The fixed core 13 is provided with a cylindrical convex portion 13a projecting from the lower end surface facing the plunger 14, and the upper end surface of the plunger 14 is provided with a concave portion 14b at a position corresponding to the convex portion 13a of the fixed core 13. Yes. The concave portion 14b of the plunger 14 is formed in a cylindrical shape having a larger diameter than the convex portion 13a of the fixed core 13, and the convex portion 13a is loosely fitted.

  The plunger 14 has a bottomed hole 14 c formed from the upper end surface, and a coiled first spring (a “first elastic member”) is formed between the convex portion 13 a of the fixed core 13 and the bottomed hole 14 c of the plunger 14. Equivalent.) 22 is compressed and held. Therefore, a force in the direction of the valve seat 9 is constantly applied to the valve body 21 by the first spring 22. The plunger 14 is formed with through holes 14 a and 14 e and adjusts the pressure of the bottomed hole 14 c according to the displacement of the first spring 22. The outer periphery of the lower end of the plunger 14 is provided with an enlarged diameter portion 14d protruding in the outer diameter direction, and a coiled second spring (corresponding to a “second elastic member”) 23 is abutted against the enlarged diameter portion 14d. And is attached to the plunger 14. The second spring 23 has a free length when the valve body 21 is in contact with the valve seat 9, and is disposed so as to have a predetermined length in the axial direction with respect to the plunger guide 15. Here, the predetermined length of the gap h refers to a length comparable to the stroke in which the plunger 14 moves up in order to control the maximum flow rate in the low flow rate adjustment range. Therefore, it is possible to arbitrarily set the low flow rate adjustment range by changing the length of the gap h. For the electromagnetic proportional valve 1 to perform low flow rate adjustment and large flow rate adjustment, the length of the gap h is set to 10 to 20% of the stroke range in which the plunger 14 moves from the fully closed position to the fully open position. It is desirable. In the present embodiment, when a current of 200 mA is supplied to the coil 11, the plunger 14 is raised by 1.00 mm to fully open the valve, and the length of the gap h is such that the plunger 14 moves from the fully closed position to the fully open position. 15% (0.15 mm) of the stroke range (1.00 mm).

  A spacer (corresponding to a “nonmagnetic member”) 24 is interposed between the fixed core 13 and the plunger 14. The spacer 24 is formed by molding a nonmagnetic material such as resin, brass, or aluminum into a donut plate shape. The spacer 24 is disposed between the fixed core 13 and the plunger 14 so as to be movable in the axial direction in a state where the convex portion 13a of the fixed core 13 is passed through the through hole in the center. Therefore, the spacer 24 is placed on the upper end surface of the plunger 14 by its own weight when not energized. When the plunger 14 is lifted, it is lifted along the convex portion 13a of the fixed core 13 and when the plunger 14 is lowered, its own weight. Therefore, it moves downward together with the plunger 14 along the convex portion 13 a of the fixed core 13.

The operation and effect of the electromagnetic proportional valve 1 having the above configuration will be described with reference to the drawings. FIG. 3 is a diagram illustrating the relationship between the attractive force characteristic and the spring characteristic, in which the vertical axis indicates the attractive force and the spring force, and the horizontal axis indicates the stroke and the spring displacement. FIG. 4 is a diagram illustrating the relationship between the current value and the flow rate.
While the current is not supplied to the coil 11, as shown in FIG. 1, in the electromagnetic proportional valve 1, the load of the first spring 22 acts on the valve body 21 via the plunger 14, and the valve body 21 is in a predetermined state. The valve seat 9 is in contact with the seal load. Therefore, even if gas is supplied to the input port 4, it is not output from the output port 5. Here, since the second spring 23 has a gap h between it and the plunger guide 15, only the load of the first spring 22 acts on the valve body 21.

  When a weak current (for example, 50 mA) is supplied to the electromagnetic proportional valve 1, an attractive force is generated in the coil 11, and the plunger 14 rises against the first spring 22. At this time, the 2nd spring 23 is lifted to the fixed core 13 side by the enlarged diameter part 14d of the plunger 14, and moves the clearance h, maintaining free length. While the second spring 23 has the gap h between the plunger guide 15, only the elastic pressure of the first spring 22 (see M <b> 1 in FIG. 3) acts on the plunger 14. Therefore, the spring characteristic (see M3 in FIG. 3) acting on the plunger 14 is the first spring until a current value (140 mA: see F3 in the figure) of 70% with respect to the rated current value (200 mA) is supplied to the coil 11. The spring constant is small and the inclination is small in accordance with the spring characteristics of 22 (see M1 in FIG. 3). Therefore, if the electromagnetic proportional valve 1 supplies current to the coil 11 within a range of 0 to 140 mA, the flow rate is linearly adjusted with respect to the current value as shown in FIG. It is possible to adjust the fine flow rate of gas with high accuracy.

  When a current value of 70% (140 mA: see F3 in the figure) is supplied to the coil 11 with respect to the rated current value (200 mA), the plunger 14 is raised 0.15 mm from the fully closed position, and the second spring 23 is moved to the plunger. It hits the guide 15. At the same time, the second spring 23 is compressed between the plunger guide 15 and the enlarged diameter portion 14d of the plunger 14 to start generating a load (see M2 in FIG. 3). Therefore, as shown in part A of FIG. 3, there is a gap between the load (M3 in the figure) obtained by combining the first spring 22 and the second spring 23 and the load of the first spring 22 (M1 in the figure). When a current value of 70% or more of the rated current value is supplied to the coil 11, the plunger 14 moves 0.15 mm from the fully closed position without stopping as shown in part B of FIG. The flow rate can continue to rise and shift from the low flow rate adjustment to the large flow rate adjustment to adjust the flow rate linearly with respect to the current value.

  When a current value equal to or greater than 70% (see F3 in the figure) of the rated current value (see F1 in the figure) is supplied to the coil 11, the plunger 14 is added to the first spring 22 as shown by M3 in FIG. The load of the second spring 23 acts. Therefore, the spring constant increases and the slope of the spring characteristic increases, and when the rated current value (200 mA: see F1 in the figure) is supplied to the coil 11, the plunger 14 is fixed from the fully closed position as shown in FIG. Ascends 1.00 mm to the core 13 side and moves to the fully open position to fully open the valve. As a result, a wide stroke range of the plunger 14 is secured, and if a current is supplied to the coil 11 within a range of 140 to 200 mA, the plunger 14 is moved from the vicinity of the fully open position in proportion to the current value, that is, from the fully closed position to the fixed core 13. The position can be adjusted within a range of 0.15 to 1.00 mm moved to the side, and the flow rate of gas can be accurately adjusted within the large flow rate adjustment range Y1, as shown in FIG.

  On the other hand, when adjusting the valve opening degree in the valve closing direction, if the current value to the coil 11 is lowered, the plunger 14 is pushed down in the valve seat direction by the elastic pressure of the first and second springs 22 and 23. The valve opening is reduced. At this time, when the valve opening is adjusted in the valve closing direction after the plunger 14 has moved to the fully open position, the end surface of the plunger 14 and the end surface of the fixed core 13 are adsorbed, and the suction force is increased. Therefore, even if the current value to the coil 11 is lowered, the state where the plunger 14 is attracted to the fixed core 13 continues, and the hysteresis increases. However, since the spacer 24 is interposed on the suction surface between the fixed core 13 and the plunger 14, illustration is omitted in the suction force characteristics shown in FIG. 3, but the suction force at the time of suction is reduced and hysteresis is reduced. Get smaller. Therefore, the electromagnetic proportional valve 1 can move the plunger 14 from the fully open position toward the valve seat 9 in accordance with the current value to the coil 11, and can accurately adjust the valve opening in the valve closing direction.

  By the way, in the electromagnetic proportional valve 1, the attracting force of the coil 11 is less likely to act on the plunger 14 as the plunger 14 is lowered and separated from the fixed core 13. However, in the electromagnetic proportional valve 1, since the convex portion 13a of the fixed core 13 is inserted into the concave portion 14b of the plunger 14, even if the plunger 14 is lowered, the inner peripheral surface of the concave portion 14b of the plunger 14 A part of the magnetic circuit is formed between the outer peripheral surface of the convex portion 13 a of the fixed core 13. Therefore, as shown by F1 to F4 in FIG. 3, the electromagnetic proportional valve 1 can suppress a sudden drop in the attractive force characteristic. From this point, the flow rate adjustment range is ensured widely and the gas is reduced in the low flow rate adjustment range. The fine flow rate can be adjusted.

  In addition, when ending flow volume adjustment, the electricity supply to the coil 11 is stopped. The plunger 14 descends in the direction of the valve seat 9 due to the elastic pressure of the first spring 22 and the second spring 23, and further contacts the valve seat 9 with the elastic pressure of the first spring 22 to connect the input port 4 and the output port 5. Cut off.

  Therefore, according to the electromagnetic proportional valve 1 of the present embodiment, the coil 11 is wound around the coil bobbin 12 having a hollow hole, the fixed core 13 is fixed to the one end opening of the coil bobbin 12, and the other end of the coil bobbin 12 is fixed. The plunger 14 is slidably inserted from the opening, and the valve body 21 attached to the tip of the plunger 14 is attached in the direction of the valve seat 9 by the first spring 22 disposed between the fixed core 13 and the plunger 14. The flow rate of the fluid supplied from the input port 4 to the output port 5 is adjusted by moving the plunger 14 in accordance with the current value to the coil 11 and separating the valve element 21 from the valve seat 9. When the valve element 21 is in contact with the valve seat 9, the second spring is free length, and is attached to the plunger 14 with a gap h of a predetermined length in the sliding direction of the plunger 14. Since a grayed 23, it is possible to eliminate the dead zone, to ensure a wide low flow adjustment range X1 (see FIG. 4).

  Further, according to the electromagnetic proportional valve 1 of the present embodiment, the length of the gap h is 15% of the stroke range in which the plunger 14 moves from the fully closed position to the fully open position. Adjustments can be made independently.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various applications are possible.

(1) For example, in the above-described embodiment, the bottomed hole 14 c is formed in the plunger 14, and the first spring 22 is contracted between the convex portion 13 a of the fixed core 13 and the bottomed hole 14 c of the plunger 14. On the other hand, an elastic member having a large spring constant such as a leaf spring may be disposed between the fixed core 13 and the plunger 14.

(2) For example, in the above embodiment, the second spring 23 is disposed between the enlarged diameter portion 14 d of the plunger 14 and the plunger guide 15. On the other hand, a second spring 23 may be disposed outside the first spring 22 and between the fixed core 13 and the plunger 14. Also in this case, the second spring 23 is arranged to have a free length with a predetermined gap in the sliding direction of the plunger 14.

(3) For example, in the said embodiment, although the convex part 13a of the fixed core 13 and the recessed part 14b of the plunger 14 were shape | molded in the column shape, you may shape | mold in a cone shape, a polygonal column shape, etc.

(4) For example, in the said embodiment, although 200 mA was made into the rated current value, a rated current value is not limited to this, It can change suitably according to the use application of an electromagnetic proportional valve.

(5) For example, in the above embodiment, the gap h is provided between the second spring 23 and the plunger guide 15. On the other hand, the gap h only needs to be provided in the sliding direction of the plunger 14. For example, one end of the second spring 23 is welded to the plunger guide 15, and the enlarged diameter portion 14 d of the plunger 14 and the second spring 23 are welded. You may make it provide the clearance gap h between other ends. Further, the spring 23 may be fixed to the plunger 14, the plunger guide 15, or the like, or may be movably mounted on the plunger 14 as long as the second spring 14 can be compressed as the plunger 14 slides.

(6) For example, in the above embodiment, the case where gas flows from the input port 4 to the output port 5 of the electromagnetic proportional valve 1 has been described. On the other hand, the electromagnetic proportional valve 1 may be connected to piping of an industrial machine or the like so as to supply a fluid from the output port 5 to the input port 4, and IN and OUT may have both pressure structures.

(7) For example, in the above embodiment, the spacer 24 is disposed between the fixed core 13 and the plunger 14 so as to be movable in the axial direction, but may be fixed to the fixed core 13 or the plunger 14.

1 is a sectional view of an electromagnetic proportional valve according to an embodiment of the present invention and shows a fully closed state. Similarly, it is sectional drawing of an electromagnetic proportional valve, Comprising: A full open state is shown. Similarly, it is a figure which shows the relationship between a suction force characteristic and a spring characteristic, Comprising: A suction force and a spring force are shown on a vertical axis | shaft, and a stroke and a spring displacement are shown on a horizontal axis. Similarly, it is a figure which shows the relationship between an electric current value and a flow volume. It is a figure which shows the relationship between the attractive force characteristic and the spring characteristic in the conventional electromagnetic proportional valve, Comprising: An attractive force and a spring force are shown on a vertical axis | shaft, and a stroke and a spring displacement are shown on a horizontal axis. It is a figure which shows the relationship between the electric current value and flow volume in the conventional electromagnetic proportional valve. It is a figure which shows an example of the conventional electromagnetic proportional valve. It is a figure which shows the relationship between the attraction | suction force characteristic and spring characteristic in the electromagnetic proportional valve shown in FIG. 7, Comprising: Attraction | suction force and spring force are shown on a vertical axis | shaft, and a stroke and spring displacement are shown on a horizontal axis | shaft. It is a figure which shows the relationship between the electric current value and flow volume in the electromagnetic proportional valve shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electromagnetic proportional valve 4 Input port 5 Output port 9 Valve seat 11 Coil 12 Coil bobbin 13 Fixed core 13a Convex part 14 Plunger 14 Concave part 21 Valve body 22 1st spring 23 2nd spring 24 Spacer h Crevice

Claims (2)

A coil is wound around a coil bobbin having a hollow hole, a fixed core is fixed to one end opening of the coil bobbin, and a plunger is slidably inserted from the other end opening of the coil bobbin. The valve body attached to the tip of the plunger is urged in the valve seat direction by the first elastic member disposed on the plunger, and the valve body is moved by moving the plunger according to the current value to the coil. In the electromagnetic proportional valve that adjusts the flow rate of the fluid supplied from the input port to the output port by separating from the valve seat,
The valve body has a second elastic member that has a free length when the valve body is in contact with the valve seat, and is attached to the plunger with a gap of a predetermined length in the sliding direction of the plunger. Solenoid proportional valve. In the electromagnetic proportional valve according to claim 1,
The length of the gap is 10 to 20% of a stroke range in which the plunger moves from a fully closed position to a fully open position.

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