JP4070525B2 - Solenoid valve and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a solenoid valve for controlling a fluid flow rate and a manufacturing method thereof.
[0002]
[Prior art]
As a prior art, there is a solenoid valve described in Japanese Patent Application No. 2001-96008.
In this solenoid valve, as shown in FIG. 10, a stator portion 120 that forms a part of a magnetic circuit is disposed on the inner periphery of a bobbin 110 around which a coil 100 is wound, and the stator portion 120 accommodates a valve element 130. A thin portion 150 that is configured integrally with the case 140 and reduces the cross-sectional area of the magnetic path is provided between the case 140 and the valve case 140.
In this configuration, when the coil 100 is energized, the magnetic flux passing through the stator portion 120 is narrowed by the thin-walled portion 150, so that magnetic saturation occurs. As a result, the magnetic flux that cannot pass through the thin portion 150 flows from the lower portion 120a of the stator portion 120 to the upper portion 120b of the stator portion 120 in the drawing, and therefore, between the upper portion 120b of the stator portion 120 in the drawing and the valve element 130. A suction force is generated, and the valve body 130 moves upward in the drawing against the biasing force of the spring 160 by the suction force.
[0003]
[Problems to be solved by the invention]
However, in the above solenoid valve, since the space 170 is formed between the thin wall portion 150 and the bobbin 110, the bobbin 110 may be softened and deformed by the heat generated by the coil 100. Further, the bobbin 110 may be deformed by the winding force of the coil 100 acting on the bobbin 110.
Further, when the bobbin 110 expands and contracts due to the cooling and heating cycle, if there is a space part 170 between the thin wall part 150 and the bobbin 110, the expansion and contraction of the bobbin 110 increases, so the coil 100 rubs and shorts. There was a fear.
[0004]
As a countermeasure against this, as shown in Japanese Patent Publication No. 11-500509, a method is conceivable in which resin is filled in a space formed between a thin portion and a bobbin. However, since the space formed between the thin wall portion and the bobbin is substantially sealed (the space is closed), if an attempt is made to fill the space with resin by injection molding, a high injection pressure (about 1000 ˜1600 kgf / cm ² ) is required, and the thin wall portion may be deformed by the resin pressure.
The present invention has been made based on the above circumstances, and an object thereof is to prevent deformation of the bobbin by filling a space portion formed between the thin portion provided in the stator portion and the bobbin with a nonmagnetic member. There is.
[0005]
[Means for Solving the Problems]
(Invention of Claim 1)
The present invention has a solenoid part formed by winding a coil around a substantially cylindrical bobbin, and a stator part that forms a part of a magnetic circuit on the inner periphery of the solenoid part, and is provided integrally with the stator part. A valve case that forms a valve accommodating portion, and a movable body that is reciprocally accommodated in the valve accommodating portion of the valve case, and that moves by receiving a suction force generated between the stator portion when the coil is energized. The valve case is an electromagnetic valve in which a concave portion is formed on the outer diameter side of the stator portion to provide a thin wall portion that reduces a magnetic path cross-sectional area,
The valve case is characterized in that when the solenoid part is assembled to the outer periphery of the stator part, the valve case is assembled with the solenoid part in a state where a nonmagnetic member is arranged in advance in a recess formed in the stator part.
[0006]
In this method, since the nonmagnetic member is disposed in the concave portion formed in the stator portion and the solenoid portion is assembled to the outer periphery of the stator portion, the thin portion is not deformed. Further, by filling the space formed between the thin wall portion and the bobbin with a nonmagnetic member, it is possible to prevent the bobbin from being softened due to the heat generation of the coil and the deformation of the bobbin due to the coil winding tension.
[0008]
Moreover, according to this invention, the nonmagnetic member arrange | positioned at a recessed part is a molded component previously shape | molded according to the shape of the recessed part, and this molded component is engage | inserted by the recessed part in the state divided | segmented into plurality. It is characterized by that.
In this method, since the molded part is merely fitted into the recess, the thin-walled portion is not deformed.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
(First Reference Example)
FIG. 1 is a cross-sectional view of the electromagnetic valve 1.
The solenoid valve 1 of the present reference example is used, for example, in a high-pressure pump (not shown) of a common rail fuel injection system, and controls the fuel discharge amount that is pumped to the common rail.
The solenoid valve 1 is composed of a valve case 3 having a stator portion 2, a valve body 4 accommodated in the valve case 3, a solenoid portion S (see FIG. 4) for driving the valve body 4 by electromagnetic force, and the like. The
[0011]
As shown in FIG. 2, the valve case 3 has a cylindrical portion 6 (valve accommodating portion of the present invention) that forms a cylinder 5, and a fuel reservoir chamber (not shown) of a high-pressure pump is formed on the wall surface of the cylindrical portion 6. A fuel port 7 is formed to open at the bottom. The fuel reservoir chamber is supplied with fuel pumped up from a fuel tank (not shown) by a feed pump (not shown).
[0012]
The fuel port 7 includes an inner port 7a that is recessed on the inner peripheral surface side (cylinder 5 side) of the cylindrical portion 6, and an outer port 7b that is recessed on the outer peripheral surface side (fuel reservoir chamber side) of the cylindrical portion 6. Consists of. However, the inner port 7a is formed in an annular shape over the entire circumference of the cylindrical portion 6, and the outer port 7b is formed at a plurality of locations in the circumferential direction and communicates with the inner port 7a.
The valve case 3 is integrally provided with a flange portion 8 for fixing the electromagnetic valve 1 to the high-pressure pump, and a hole 8a for inserting a fixing bolt (not shown) is formed in the flange portion 8. ing.
[0013]
The stator portion 2 is disposed on the inner periphery of the solenoid portion S and forms a part of the magnetic circuit. As shown in FIG. 2, the stator portion 2 is provided by extending the cylindrical portion 6 of the valve case 3, and a concave portion 9 is formed on the outer diameter side of the stator portion 2 to reduce a magnetic path cross-sectional area. 10 is provided. If the thickness of the thin portion 10 is too thin, a problem in strength occurs, and if it is too thick, the magnetic flux flows too much and the performance deteriorates. Therefore, it is desirable that the thickness of the thin portion 10 be adjusted to an optimum value in consideration of strength and magnetic characteristics. In this reference example, the thickness is set to 0.3 to 0.7 mm. In addition, the taper part 11 in which thickness becomes thick gradually is provided in the non-case side (upper side of FIG. 1) of the thin part 10.
[0014]
The valve case 3 having the stator portion 2 is finished into a desired shape (see FIG. 2) by cutting or the like, and then the resin 9 is filled into the concave portion 9 formed in the stator portion 2 by injection molding. (See FIG. 3). At this time, the resin pressure at the time of injection molding acts on the thin portion 10, but since the shape of the recess 9 is simple and the resin 12 easily flows into the recess 9, the resin pressure is applied to the extent that the thin portion 10 does not deform. It can be lowered (for example, about 500 kgf / cm ² ).
The valve case 3 is made of a soft magnetic material such as electromagnetic stainless steel (ferritic stainless steel SUS13 or the like) that can pass magnetic flux, and a thin hardened layer by NiP plating, for example, is provided on the surface of the cylinder 5. Yes.
[0015]
As shown in FIG. 1, the valve body 4 is inserted into the cylinder 5 of the valve case 3 so as to be able to reciprocate, and is urged by the spring 13 in the valve closing direction (downward in FIG. 1). It abuts against the fixed stopper 14 and is stationary. The valve body 4 has an internal passage 15 that penetrates the inside of the valve body 4 in the vertical direction of FIG. 1, and one end of the internal passage 15 passes through a communication hole 14 a formed in the stopper 14. ) And the other end of the internal passage 15 communicates with the internal space 16 of the stator portion 2 that houses the spring 13. Thereby, since the fuel pressure does not act in the sliding direction of the valve body 4 (up and down direction in FIG. 1), the valve body 4 can be stably operated.
[0016]
The valve body 4 is formed with a metering hole 17 penetrating in the thickness direction. The metering hole 17 is formed in a slit shape having the same width along the sliding direction of the valve body 4, and when the valve body 4 is lifted by a predetermined amount or more (moves upward in FIG. 1), the valve case 3. The fuel port 7 communicates with the fuel port 7, and the communication area with the fuel port 7 changes according to the lift amount of the valve body 4 (determined by the amount of current supplied to the coil 18), and the fuel passes through the fuel port 7. Variable amount. When the valve body 4 is in contact with the stopper 14 and is stationary (when the valve is closed), the metering hole 17 does not communicate with the fuel port 7 as shown in FIG. The internal passage 15 and the fuel reservoir chamber of the high pressure pump are blocked.
[0017]
The valve body 4 is provided with an armature portion 4a that not only adjusts the flow rate of the fuel but also receives the electromagnetic force of the solenoid portion S (see FIG. 1). Therefore, the valve body 4 is made of a soft magnetic material such as pure iron or low carbon steel that can pass magnetic flux, and a thin hardened layer formed by, for example, NiP plating is provided on the surface thereof. As a result, it is possible to improve the wear resistance and reduce the frictional force while maintaining the magnetic characteristics, and the valve body 4 can move smoothly in the cylinder 5.
In the electromagnetic valve 1 of this reference example, the valve body 4 contacts the stopper 14 when the coil 18 is not energized to maintain the valve closed state, and the valve body 4 is lifted and opened when the coil 18 is energized ( The metering hole 17 communicates with the fuel port 7).
[0018]
The solenoid part S is formed by winding a coil 18 around a resin bobbin 19 and is integrated with a metal housing 20 (this housing 20 forms a part of a magnetic circuit) and a connector part 21 as a subassembly SA. Is configured.
The assembling procedure of the subassembly SA will be described with reference to FIG.
(A) The coil 18 is wound around the bobbin 19 to form the solenoid part S.
(B) The housing 20 is assembled so as to cover the outer periphery of the solenoid part S.
(C) The connector portion 21 is formed on the upper portion of the housing 20 by injection molding.
As shown in FIG. 5, the subassembly SA is assembled to the valve case 3 and integrated by, for example, laser welding (or caulking, press-fitting, etc.), and then the spring 13, the valve body 4, the stopper 14, O The ring 22 is assembled to complete the electromagnetic valve 1 shown in FIG.
[0019]
(Effect of the first reference example)
In the solenoid valve 1 of the present reference example, the recess 9 formed in the stator portion 2 is filled with the resin 12, so that no space is formed on the outer periphery of the thin portion 10 with the bobbin 19. Thereby, even if the bobbin 19 is softened due to the heat generated by the coil 18, the bobbin 19 is not deformed, and even if the winding force of the coil 18 acts on the bobbin 19, the bobbin 19 is not deformed.
Furthermore, even if a cooling cycle is applied, deformation (expansion and contraction) of the bobbin 19 can be suppressed, so that a short circuit due to friction of the coil 18 can be avoided.
[0020]
In this reference example, since the injection molding is performed before the subassembly SA is assembled to the valve case 3, the resin pressure at the time of molding can be lowered to such an extent that the thin portion 10 is not deformed. As a result, since the thin portion 10 is not deformed during injection molding, the thin portion 10 does not interfere with the valve body 4 and smooth sliding of the valve body 4 can be ensured.
Although a thin hardened layer is provided on the surface of the cylinder 5 of the valve case 3 and the surface of the valve body 4, as the hardening treatment, in addition to the NiP plating described in the reference example, the surface of the cylinder 5 of the valve case 3 and the valve Soft nitriding may be performed on the surface of the body 4 or a ceramic coating such as DLC (diamond-like carbon) may be applied.
[0021]
(First Embodiment)
FIG. 6 is a sectional view of the valve case 3.
The present embodiment is an example in which a molded part 23 fitted into the recess 9 is used as a means for filling the recess 9 (see FIG. 2) formed in the stator portion 2.
As shown in FIG. 7, the molded part 23 is resin-molded in advance in accordance with the shape of the concave portion 9 and is divided into two semicircular shapes in order to facilitate fitting into the concave portion 9.
The molded part 23 is fitted into the recess 9 before the subassembly SA described in the first reference example is assembled to the valve case 3 (see FIG. 6).
[0022]
Also in this method, since the space formed between the bobbin 19 and the thin portion 10 can be filled with the molded part 23, the deformation of the bobbin 19 can be prevented as in the first reference example.
Further, in this embodiment, there is no need to perform injection molding to fill the recess 9 with resin, and only the pre-molded molded part 23 is fitted into the recess 9, so there is no fear that the thin portion 10 is deformed. .
The molded part 23 may be divided into three or more parts. Further, the molded part 23 is not necessarily made of resin, and may be a non-magnetic member that does not pass magnetism (for example, austenitic stainless steel SUS304).
[0023]
( Second reference example)
FIG. 8 is a cross-sectional view of the valve case 3 with the subassembly SA assembled. This reference example is an example in which a filling passage 24 for filling the resin 12 is provided in a space formed between the thin wall portion 10 and the bobbin 19.
As shown in FIG. 8, the filling passage 24 is formed between the inner peripheral surface of the bobbin 19 and the flat surface 2 a (see FIG. 9) formed in the stator portion 2 in a state where the subassembly SA is assembled to the valve case 3. Formed between.
[0024]
As shown in FIG. 9, the stator portion 2 is provided with a flat surface 2 a that reduces the outer diameter of the stator portion 2 from the recess 9 to the opposite case side (upper side in FIG. 9). Thereby, when the subassembly SA is assembled to the valve case 3, a gap is formed between the inner peripheral surface of the bobbin 19 and the flat surface 2 a, and the gap is formed as the filling passage 24.
[0025]
According to this configuration, since the resin 12 can be easily filled into the space formed between the thin portion 10 and the bobbin 19 using the filling passage 24, the thin portion 10 can reduce the resin pressure during the injection molding. It is possible to keep it low to the extent that it does not deform.
Further, in the method of this reference example, the resin 12 can be filled into the space portion simultaneously with the molding of the connector portion 21 by one injection molding, so that the number of injection moldings can be reduced as compared with the case where the injection molding is performed separately. And cost reduction is possible.
[0026]
(Modification)
In the above embodiment, the armature portion 4a is provided integrally with the valve body 4. However, the armature portion 4a may be formed as a separate part so that the valve body 4 can be moved integrally with the armature portion 4a.
Moreover, although the Example which used the solenoid valve 1 of this invention for the high pressure pump of the common rail type fuel injection system was described, besides this, for example, it applies to an electromagnetic type fuel injection valve, or ABS (anti-lock brake system) Etc.) and other hydraulic oil hydraulic control devices.
[0027]
Furthermore, in the above embodiment, the normally closed type electromagnetic valve 1 that closes when the coil 18 is not energized is described. However, a normally open type electromagnetic valve that opens when the coil 18 is not energized may be used. Or it is good also as a structure which can hold | maintain few flow-path areas (valve-opening amount) at the time of the deenergization of the coil 18. FIG. For example, the metering hole 17 of the valve body 4 and the fuel port 7 of the valve case 3 may be slightly communicated, and the flow passage area may be increased as the amount of current supplied to the coil 18 is increased.
Further, in the solenoid valve 1 described in the embodiment, the lift amount (flow path area) of the valve body 4 is determined according to the amount of current supplied to the coil 18. An ON / OFF type solenoid valve that moves between positions may be used.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a solenoid valve (first reference example).
FIG. 2 is a cross-sectional view of a valve case.
FIG. 3 is a cross-sectional view of a valve case showing a state in which a recess is filled with resin.
FIG. 4 is a process diagram showing a procedure for assembling a sub-assembly.
FIG. 5 is a cross-sectional view showing a state where a subassembly is assembled to a valve case.
FIG. 6 is a cross-sectional view of the valve case ( first embodiment).
FIG. 7 is a plan view (a) and a sectional view (b) of a molded part ( first embodiment).
FIG. 8 is a cross-sectional view showing a state where a subassembly is assembled to a valve case ( second reference example).
FIG. 9 is a cross-sectional view of a valve case ( second reference example).
FIG. 10 is a cross-sectional view of a solenoid valve (prior art).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Solenoid valve 2 Stator part 3 Valve case 4 Valve body (movable body)
6 Cylindrical part (valve accommodating part)
9 Concave portion 10 Thin portion 12 Resin (non-magnetic member)
18 Coil 19 Bobbin 23 Molded part (Non-magnetic member)
24 Filling passage S Solenoid part

Claims (1)

A solenoid portion formed by winding a coil around a substantially cylindrical bobbin;
A valve case that has a stator portion that forms part of the magnetic circuit on the inner periphery of the solenoid portion, and that forms a valve housing portion that is provided integrally with the stator portion;
A movable body that is accommodated in the valve accommodating portion of the valve case so as to be reciprocally movable, and that moves by receiving a suction force generated between the stator portion when the coil is energized;
The valve case is a solenoid valve provided with a thin portion that has a recess formed on the outer diameter side of the stator portion to reduce a magnetic path cross-sectional area,
When assembling the solenoid part on the outer periphery of the stator part, the valve case is assembled with the solenoid part in a state in which a nonmagnetic member is disposed in advance in the recess formed in the stator part ,
The non-magnetic member disposed in the recess is a molded part molded in advance according to the shape of the recess, and the molded part is fitted into the recess in a state of being divided into a plurality of parts. A method for manufacturing a solenoid valve .

Images