JP2014031838A - Electromagnetic valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a normally open type electromagnetic valve capable of reducing spring load when starting energization and increasing the spring load in an operational area with large magnetic attraction force while avoiding reduction in a magnetic pole surface.SOLUTION: Two springs 36, 38 are arranged in series and a spring receiving member 34 is arranged between the two springs 36, 38. In an operational area where magnetic attraction force is low and a position of a valve body 20 is closer to the fully opened position side than an intermediate position, the spring receiving member 34 is not abutted on a sleeve 12 or an armature 22 and both deflections of the two springs 36, 38 are changed, so that a synthetic spring constant is reduced. In an operational area where the magnetic attraction force is large and the position of the valve body 20 is closer to the fully closed position side than the intermediate position, the spring receiving member 34 is abutted on the sleeve 12 and the deflection of one spring 36 is not changed, so that the spring constant is increased.

Description

  The present invention relates to a normally open type electromagnetic valve that controls the position of a valve body by balancing a magnetic attractive force, a spring load, and a fluid force.

  Conventionally, in a normally open type solenoid valve, a magnetic attraction force corresponding to the energization amount is generated in the drive means, and the position of the valve body is controlled by the balance between the magnetic attraction force, the spring load, and the fluid force, Those that control pressure are known.

  In this normally open type solenoid valve, the spring load at the start of energization is reduced while the valve opening is small in order to reduce the amount of fluid pressure change when energization of the drive means is started from the fully open state. In order to ensure that the valve is opened against the sliding resistance when energization to the drive means is stopped, the operating region with a large magnetic attraction force (that is, the valve opening degree for normally open solenoid valves) It is desirable to increase the spring load in a small operating region).

  Such requirements for normally open solenoid valves can be achieved by reducing the spring constant in the operating region where the magnetic attractive force is small and increasing the spring constant in the operating region where the magnetic attractive force is large. it can.

  On the other hand, in a normally closed type solenoid valve, a magnetic attraction force corresponding to the energization amount is generated in the drive means, and the position of the valve body is controlled by the balance between the magnetic attraction force, the spring load, and the fluid force, One that controls the pressure has been proposed (see, for example, Patent Document 1).

  In addition, this electromagnetic valve changes the spring constant according to the position of the valve body. Specifically, two springs are arranged in series, and a spring receiving member is arranged between the two springs. In the operating region where the magnetic attractive force is small (that is, the operating region where the valve opening is small in a normally closed solenoid valve), the spring receiving member is locked to the locking portion, and only one spring is used. In the operating region where only the spring load of the spring is deflected and the magnetic attraction force is large (that is, in the normally closed type solenoid valve, the valve opening is large), the spring receiving member is engaged. Apart from the stop, the two springs are bent together so that their combined spring load acts on the armature.

  Since the two springs are arranged in series, the combined spring constant of the two springs when the spring receiving member is separated from the locking portion is smaller than the spring constant of one of the springs. In other words, the spring constant is large in the operating region where the magnetic attractive force is small, and the spring constant is small in the operating region where the magnetic attractive force is large.

  In another specific example, two springs are arranged in parallel, and in an operating region where the magnetic attractive force is small, only the spring load of one spring acts on the armature, and in an operating region where the magnetic attractive force is large, two springs Both spring loads of the spring act on the armature.

  Therefore, the spring constant is small in the operating region where the magnetic attractive force is small, and the spring constant is large in the operating region where the magnetic attractive force is large.

JP 2008-14397 A

  In an electromagnetic valve in which two springs described in Patent Document 1 are arranged in series, a spring constant is large in an operating region where the magnetic attractive force is small, and a spring constant is small in an operating region where the magnetic attractive force is large.

  Therefore, even if a configuration in which two springs are arranged in series is applied to a normally open type solenoid valve, the above-described requirement for a normally open type solenoid valve (that is, the spring load at the start of energization is reduced, In the operating region where the suction force is large, it is impossible to increase the spring load).

  On the other hand, in the electromagnetic valve in which two springs described in Patent Document 1 are arranged in parallel, the spring constant is small in the operating region where the magnetic attractive force is small, and the spring constant is large in the operating region where the magnetic attractive force is large. When a configuration in which two springs are arranged in parallel is applied to a normally open type solenoid valve, the above-described requirements for a normally open type solenoid valve can be achieved. However, since the springs are installed in parallel, there arises a problem that the magnetic pole surface is reduced and the generated magnetic attractive force is reduced.

  In view of the above points, in the normally open type solenoid valve, the present invention reduces the spring load at the start of energization while avoiding the reduction of the magnetic pole surface, and reduces the spring load in the operation region where the magnetic attractive force is large. The purpose is to enlarge.

  In order to achieve the above object, according to the first aspect of the present invention, a magnetic circuit is configured and a housing (10) having a housing hole (102) and a fluid passage (16) through which a fluid flows is disposed in the housing hole Sleeve (12), rod (14) slidably inserted into the sleeve, fluid passage hole (180) integrated with the housing and communicating with the fluid passage, and opening of the fluid passage hole A valve body (18) having a valve seat (181) surrounding the valve body, a valve body (20) joined to one end of the rod to change the opening degree of the fluid passage hole, and joined to the other end of the rod, and magnetic attractive force Armature (22) that operates in response to the power, driving means (10, 24, 30, 32) for generating a magnetic attractive force according to the amount of energization to drive the armature in the valve closing direction, and countering the magnetic attractive force Spring means (34, 36, 38) for urging the armature in a direction to adjust the position of the valve body by balancing the magnetic attraction force, the spring load of the spring means, and the fluid force exerted on the valve body by the fluid. In the solenoid valve which is controlled and the fluid passage hole is fully opened when the drive means is not energized, the spring means is a compression coil spring arranged in series between the sleeve and the armature and along the axial direction of the rod. Two springs (36, 38) and a spring receiving member (34) which is arranged between the two springs and abuts against the sleeve or the armature in the operation region where the position of the valve body is closer to the fully closed position side than the intermediate position In the operating region where the position of the valve body is closer to the fully open position side than the intermediate position, the amount of deflection of the two springs changes as the armature moves, and the position of the valve body is fully closed relative to the intermediate position. On the position side The have operating region, by the spring receiving member is brought into contact with the sleeve or armature, the amount of deflection of one of the spring of the two springs is characterized by being configured so as not to be changed.

  According to this, since the two springs are arranged in series, the magnetic pole surface becomes larger than the case where the two springs are arranged in parallel. Also, in the operating region where the position of the valve body is closer to the fully open position side than the intermediate position, the amount of deflection of the two springs arranged in series changes, so the combined spring constant becomes smaller and the position of the valve body becomes the intermediate position. In the operating region closer to the fully closed position side, the spring constant increases because the amount of bending of one of the two springs does not change.

  Therefore, in the normally open type solenoid valve, it is possible to reduce the spring load at the start of energization while avoiding the reduction of the magnetic pole surface, and to increase the spring load in the operation region where the magnetic attractive force is large.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

It is front sectional drawing which shows the structure of the solenoid valve which concerns on one Embodiment of this invention. It is a top view which shows the spring receiving member of FIG. It is III-III sectional drawing of FIG. It is front sectional drawing of the principal part which shows the other operating state of the solenoid valve of FIG. It is a figure which shows the relationship between the spring load and valve opening degree of the solenoid valve of FIG. It is a time chart with which it uses for operation | movement description of the solenoid valve of FIG.

  The electromagnetic valve according to the present embodiment is an electromagnetic valve that controls the fuel pressure in the common rail by opening and closing the flow path for discharging the high-pressure fuel in the common rail to the low-pressure part in the accumulator fuel injection device for the compression ignition type internal combustion engine. Used.

  As shown in FIGS. 1 to 3, the electromagnetic valve includes a cylindrical housing 10 made of a magnetic metal and forming a magnetic circuit. A cylindrical housing first tube portion 100 and a cylindrical housing second tube portion 101 are formed in the housing 10 continuously in the axial direction.

  The housing first tube portion 100 is formed with a housing first hole 102 in a cylindrical space at the center in the radial direction. The housing second tube portion 101 is formed with a housing second hole 103 having a cylindrical space having an inner diameter larger than that of the housing first hole 102.

  A cylindrical sleeve 12 made of a non-magnetic metal such as stainless steel is disposed in the housing first hole 102. A cylindrical rod 14 made of a magnetic metal is slidably inserted into the sleeve 12.

  The sleeve 12 is shorter than the housing first hole 102, and is located at an intermediate portion in the axial direction of the housing first hole 102. As a result, in the space of the housing first hole 102, the space closer to the housing second hole 103 than the sleeve 12 functions as an accommodating portion for accommodating a spring receiving member 34 and the like, which will be described later. The space on the second hole side functions as a fluid passage 16 through which fuel flows. The fluid passage 16 is connected to a fuel tank (not shown).

  A cylindrical valve body 18 is fixed to the end of the first housing cylinder 100 by caulking. The valve body 18 is formed with a fluid passage hole 180 communicating with the fluid passage 16 at the radial center. Further, the valve body 18 is formed with a tapered valve seat 181 surrounding the fluid passage hole 180 on the surface on the fluid passage 16 side. The fluid passage hole 180 is connected to a common rail (not shown).

  A spherical valve body 20 made of metal is joined to the end of the rod 14 on the valve body 18 side. The valve body 20 moves in the axial direction of the rod 14 together with the rod 14, thereby changing the opening degree of the fluid passage hole 180 (hereinafter referred to as a valve opening degree).

  A cylindrical armature 22 made of a magnetic metal and forming a magnetic circuit is joined to the end of the rod 14 on the side opposite to the valve body. The armature 22 is disposed in the housing second hole 103. The armature 22 is formed with a recess 220 into which an end of a spring described later is inserted.

  An air gap G is formed between the armature magnetic pole surface 221 which is a surface facing the housing first cylindrical portion 100 in the armature 22 and the housing magnetic pole surface 104 which is a surface facing the armature 22 in the housing first cylindrical portion 100. Has been.

  Then, the armature 22 is attracted to the housing magnetic pole surface 104 side by the magnetic attraction force, and the rod 14 and the valve body 20 are moved to the valve body 18 side together with the armature 22. In other words, the valve opening is reduced when the armature 22 is attracted to the housing magnetic pole surface 104 side by the magnetic attraction force.

  Hereinafter, in this specification, the rod 14, the valve body 20, and the armature 22 are collectively referred to as the movable members 14, 20, and 22.

  A bottomed cylindrical stator core 24 that is made of a magnetic metal and forms a magnetic circuit is disposed in the housing second cylindrical portion 101 so as to face the armature 22. The housing 10 and the stator core 24 are hermetically joined by welding via a ring-shaped collar 26 made of a nonmagnetic metal such as stainless steel.

  The collar 26 restricts the flow of magnetic flux between the housing 10 and the stator core 24. More specifically, a part of the inner peripheral surface of the collar 26 faces the outer peripheral surface of the armature 22, and the armature Bypassing 22, the magnetic flux flowing between the housing 10 and the stator core 24 is suppressed.

  A stopper 28 is disposed at the bottom of the stator core 24 so as to face the rod 14. When the rod 14 comes into contact with the stopper 28, the moving range of the movable members 14, 20, 22 toward the stator core 24 is restricted.

  A cylindrical coil 30 that forms a magnetic field when energized is disposed in the housing second cylindrical portion 101 and on the outer peripheral side of the stator core 24. In addition, a disc-shaped retaining nut 32 that is made of a magnetic metal and forms a magnetic circuit is screwed to the end of the housing second cylindrical portion 101. The housing 10, the stator core 24, the coil 30, and the retaining nut 32 constitute the drive means of the present invention.

  Of the space of the housing first hole 102, the space closer to the housing second hole 103 than the sleeve 12 is a cylindrical spring receiving member 34 made of a nonmagnetic metal or resin, and a first spring 36 made of a compression coil spring. , And a second spring 38 made of a compression coil spring is disposed. The spring receiving member 34 is slidable with respect to the housing first tube portion 100. The first spring 36 and the second spring 38 are disposed in series between the sleeve 12 and the armature 22 and along the axial direction of the rod 14.

  The movable members 14, 20, and 22 are urged by the first spring 36 and the second spring 38 in the direction in which the valve opening increases (that is, in the valve opening direction). Therefore, this solenoid valve is a normally open type solenoid valve. The spring receiving member 34, the first spring 36, and the second spring 38 constitute the spring means of the present invention.

  The spring receiving member 34 includes a flat spring receiving plate portion 340 that is sandwiched between the first spring 36 and the second spring 38.

  In the spring receiving plate portion 340, a spring receiving plate portion hole 341 into which the rod 14 is slidably inserted is formed in the center portion in the radial direction.

  Further, the spring receiving plate portion 340 includes a space on the sleeve 12 side of the spring receiving plate portion 340 and a space on the armature 22 side of the spring receiving plate portion 340 in a state where the rod 14 is inserted in the inner peripheral portion thereof. A communication passage 342 is formed for communicating the two. Three communication paths 342 are arranged at equal intervals along the circumferential direction of the spring receiving plate portion 340.

  The space in which the fluid passage 16 and the armature 22 are disposed communicates with the gap between the rod 14 and the sleeve 12 and the communication passage 342, and the passage area of the communication passage 342 is the passage between the rod 14 and the sleeve 12. It is set larger than the area. As a result, the fuel can easily move between the fluid passage 16 and the space in which the armature 22 is disposed, so that the fluid resistance when the armature 22 operates can be reduced.

  The spring receiving member 34 is a cylindrical spring receiving first tube portion 343 that extends from the end surface on the outer peripheral side of the spring receiving plate portion 340 and along the axial direction of the rod 14 toward the sleeve 12 side. And a cylindrical spring receiving second cylindrical portion 344 extending from the end face on the armature 22 side of the spring receiving plate portion 340 along the axial direction of the rod 14 and toward the armature 22 side.

  At least a part of the first spring 36 is inserted into the spring receiver first tube portion 343, one end side end surface is in contact with the spring receiving plate portion 340, and the other end side end surface is in contact with the sleeve 12. The first spring 36 is positioned in the spring radial direction by the spring receiver first tube portion 343 and the rod 14.

  A part of the second spring 38 is inserted into the spring receiver second cylindrical portion 344, one end side end surface is in contact with the spring receiving plate portion 340, and the other end side end is inserted into the recess 220 of the armature 22. . The second spring 38 is positioned in the spring radial direction by the second cylindrical portion 344, the concave portion 220, and the rod 14.

  As shown in FIG. 1, in the state where the rod 14 is in contact with the stopper 28, the valve body 20 is farthest from the valve seat 181 and the fluid passage hole 180 is fully opened, so that the valve opening is maximized. Yes. In the operation region where the position of the valve body 20 is closer to the fully opened position side than the intermediate position, the tip of the spring receiving first cylindrical portion 343 is not in contact with the sleeve 12.

  In addition, as shown in FIG. 4, the tip of the spring receiving first cylindrical portion 343 comes into contact with the sleeve 12 in the operation region where the position of the valve body 20 is closer to the fully closed position side than the intermediate position.

  The tip of the spring receiving second tube portion 344 and the armature 22 are not in contact with each other regardless of the position of the valve body 20.

  Next, the operation of the electromagnetic valve according to this embodiment will be described.

  The movable members 14, 20, and 22 are urged in the valve opening direction by the spring loads of the first spring 36 and the second spring 38, and the valve members 20 are moved in the valve opening direction by the fluid force exerted on the valve body 20 by the high-pressure fuel in the common rail. Be energized.

  Further, when the coil 30 is energized, the movable members 14, 20, and 22 are biased toward the valve closing direction by a magnetic attractive force generated between the armature magnetic pole surface 221 and the housing magnetic pole surface 104.

  Here, since the flow of magnetic flux between the housing 10 and the rod 14 is suppressed by the sleeve 12 made of a non-magnetic material, the magnetic flux density between the armature magnetic pole surface 221 and the housing magnetic pole surface 104 is increased, and magnetic The suction force can be increased.

  When the coil 30 is not energized, that is, when no magnetic attractive force is generated, the movable members 14, 20, and 22 are driven to the fully open position by the spring load and the fluid force. At this time, the fluid passage hole 180 is fully open, and the high-pressure fuel in the common rail is discharged to the fuel tank through the fluid passage hole 180 and the fluid passage 16, but the fuel pressure in the common rail (hereinafter referred to as rail pressure) is reduced. For example, the passage area of the fluid passage hole 180 is set so as to be maintained at about 20 MPa.

  When the coil 30 is energized from such a state, a magnetic attractive force is generated, and the movable members 14, 20, and 22 are driven in the valve closing direction against the spring load and the fluid force. As the current supplied to the coil 30 increases, the valve opening gradually decreases and the rail pressure gradually increases.

  Here, if the spring constant of the first spring 36 is k1, the spring constant of the second spring 38 is k2, and the combined spring constant of the first spring 36 and the second spring 38 is K, an operating region where the valve opening is large (ie, In the operation region where the magnetic attractive force is small and the position of the valve body 20 is closer to the fully open position side than the intermediate position), the tip of the spring receiving first cylindrical portion 343 is not in contact with the sleeve 12 and is therefore arranged in series. The amount of deflection of both the first spring 36 and the second spring 38 changes, and K = (k1 / k1 + k2) · k2.

  On the other hand, in the operating region where the valve opening is small (that is, the operating region where the magnetic attractive force is large and the position of the valve body 20 is closer to the fully closed position than the intermediate position), the tip of the spring receiving first cylinder portion 343 is the sleeve. 12, the movement of the spring receiving member 34 is restricted, and the amount of bending of the first spring 36 does not change. Therefore, only the amount of bending of the second spring 38 changes, and K = k2.

  Since (k1 / k1 + k2) <1, the combined spring constant K decreases in the operating region where the valve opening is large, and the combined spring constant K increases in the operating region where the valve opening is small. As a result, as shown in FIG. 5, the spring load gradually increases in the process of changing the valve opening from the fully open to the intermediate opening, and the spring load is changed in the process of changing the valve opening from the intermediate opening to the fully closed. Increases rapidly. In other words, the spring load is small in the operation region where the valve opening is large, and the spring load is large in the operation region where the valve opening is small.

  Note that k1 = k2 or k1 ≠ k2. Incidentally, when k1 = k2, K = 1/2 · k2 in the operating region where the valve opening is large.

  FIG. 6 shows the change in rail pressure when the current supplied to the coil 30 is increased stepwise. In FIG. 6, the solid line indicates the change in rail pressure of the solenoid valve according to the present embodiment, and the broken line indicates the change in rail pressure of the conventional solenoid valve using one spring.

  As shown in FIG. 6, when the current supplied to the coil 30 is increased stepwise, the rail pressure starts increasing at a certain point and then gradually increases stepwise. And since the spring load at the time of an energization start (namely, at the time of full opening) is small, the amount of pressure changes at the time of a rail pressure rise start becomes small. Specifically, the electromagnetic valve according to the present embodiment can reduce the amount of change in pressure at the start of the increase in rail pressure by 60% compared to a conventional electromagnetic valve.

  On the other hand, since the spring load in the operating region where the magnetic attractive force is large and the valve opening is small is large, when the energization to the coil 30 is stopped in the operating state where the magnetic attractive force is large, the sliding resistance is resisted. The valve can be opened reliably.

  As described above, in the present embodiment, since the first spring 36 and the second spring 38 are arranged in series, the armature magnetic pole face 221 and the housing magnetic pole face are compared with the case where the two springs are arranged in parallel. 104 can be enlarged. Further, the combined spring constant K is smaller in the operation region where the position of the valve body 20 is closer to the fully open position side than the intermediate position, and the combined spring constant K is set in the operation region where the position of the valve body 20 is closer to the fully closed position side than the intermediate position. Can be increased.

  Therefore, in the normally open type solenoid valve, while avoiding the armature magnetic pole surface 221 and the housing magnetic pole surface 104 from becoming smaller, the spring load at the start of energization is reduced, and the spring load is increased in the operating region where the magnetic attractive force is large. Can be bigger.

  In the above embodiment, the housing 10 and the valve body 18 are integrated after being formed as separate members. However, the housing 10 and the valve body 18 may be formed as one member.

  Further, in the above-described embodiment, the tip of the spring receiving first cylinder portion 343 and the sleeve 12 do not contact each other in the operation region where the position of the valve body 20 is closer to the fully open position side than the intermediate position, and the position of the valve body 20 is The operating region closer to the fully closed position side than the intermediate position is in contact, while the tip of the spring receiver second tube portion 344 and the armature 22 are not in contact with each other regardless of the position of the valve body 20. The distal end of the first cylindrical portion 343 and the sleeve 12 do not come into contact with each other regardless of the position of the valve body 20, while the distal end of the spring receiving second cylindrical portion 344 and the armature 22 Alternatively, the operating region close to the fully open position may not contact but the valve body 20 may contact in the operating region closer to the fully closed position than the intermediate position. In this case, in the operation region where the position of the valve body 20 is closer to the fully closed position side than the intermediate position, the amount of bending of the second spring 38 does not change, and only the amount of bending of the first spring 36 changes.

  Furthermore, in the said embodiment, although this invention was applied to the solenoid valve which controls the fuel pressure in a common rail, this invention is applicable also to the solenoid valve which controls the fluid pressure in another use.

10 Housing (drive means)
12 Sleeve 14 Rod 16 Fluid passage 18 Valve body 20 Valve body 22 Armature 24 Stator core (drive means)
30 coils (drive means)
32 Retaining nut (drive means)
34 Spring receiving member (spring means)
36 First spring (spring means)
38 Second spring (spring means)
102 Housing first hole (housing hole)
180 Fluid passage hole 181 Valve seat

Claims (5)

A housing (10) comprising a magnetic circuit and having a housing hole (102) and a fluid passage (16) through which fluid flows;
A sleeve (12) disposed in the housing bore;
A rod (14) slidably inserted into the sleeve;
A valve body (18) integrated with the housing and having a fluid passage hole (180) communicating with the fluid passage and a valve seat (181) surrounding the opening of the fluid passage hole;
A valve body (20) joined to one end of the rod to change the opening of the fluid passage hole;
An armature (22) joined to the other end of the rod and actuated by magnetic attraction;
Drive means (10, 24, 30, 32) for generating a magnetic attractive force according to the amount of energization to drive the armature in the valve closing direction;
Spring means (34, 36, 38) for biasing the armature in a direction opposite to the magnetic attractive force;
The position of the valve body is controlled by a balance between the magnetic attractive force, the spring load of the spring means, and the fluid force exerted on the valve body by the fluid. When the drive means is not energized, the fluid passage hole is fully opened. In the solenoid valve
The spring means is
Two springs (36, 38) comprising compression coil springs arranged in series between the sleeve and the armature and along the axial direction of the rod, and the two springs, A spring receiving member (34) that abuts against the sleeve or the armature in an operating region where the body position is closer to the fully closed position side than the intermediate position;
In the operation region where the position of the valve body is closer to the fully open position side than the intermediate position, the amount of deflection of the two springs changes together with the movement of the armature,
In an operation region where the position of the valve body is closer to the fully closed position side than the intermediate position, the amount of deflection of one of the two springs changes as the spring receiving member comes into contact with the sleeve or the armature. A solenoid valve characterized by not being configured.   The solenoid valve according to claim 1, wherein the sleeve is made of a non-magnetic material. One end of the housing hole communicates with the fluid passage,
The other end of the housing hole communicates with a space in which the armature is disposed,
The space in which the fluid passage and the armature are arranged communicates with each other through a gap between the rod and the sleeve and a communication passage (342) formed in the spring receiving member,
The solenoid valve according to claim 1 or 2, wherein a passage area of the communication passage is larger than a passage area between the rod and the sleeve. The spring receiving member includes a spring receiving plate portion (340) sandwiched between the two springs, and a cylindrical spring receiving first tube extending from one end side of the spring receiving plate portion along the axial direction of the rod. A portion (343) and a cylindrical spring receiver second tube portion (344) extending from the other end side of the spring receiving plate portion along the axial direction of the rod,
An end of one of the two springs is inserted into the first spring receiver cylindrical portion, and an end of the other of the two springs is inserted into the second spring receiver cylindrical portion. The electromagnetic valve according to any one of claims 1 to 3, characterized in that:   The solenoid valve according to any one of claims 1 to 4, wherein the armature includes a recess (220) into which an end of the spring on the armature side of the two springs is inserted.

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