JP2010133490A - Solenoid valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce leakage of magnetic flux at an outer peripheral corner part of an armature. <P>SOLUTION: In this solenoid valve including a ring-like collar 87 for connecting a stator core 86 to a valve body 80 at an end on the armature 83 side in the stator core 86, and restricting the flow of magnetic flux between the stator core 86 and the valve body 80, a recessed part 870 is formed on the inner peripheral face of the collar 87. Chamfering of the outer peripheral corner part on the stator core 86 side in the armature 83 is not required, and the distance between the outer peripheral corner part of the armature 83 and the stator core 86 becomes shorter, so that leakage of magnetic flux at that portion is reduced and responsiveness upon energizing a coil 90 can be improved. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electromagnetic valve that drives an armature by a magnetic attractive force.

  Conventionally, a pressure accumulation type fuel injection device for a diesel engine opens a pressure reducing valve at the time of deceleration to discharge high pressure fuel in the pressure accumulator to a fuel tank, and rapidly reduces the pressure in the pressure accumulator to a target value. ing.

  In recent years, pressure-reducing valves are required to have high-response pressure controllability while being driven by a battery for the purpose of reducing the cost of the control circuit. To achieve this requirement, the inventors have formed a magnetic circuit together. Solenoid valve with improved responsiveness by bypassing the armature and suppressing the magnetic flux flowing between the stator core and the valve body by providing a ring-shaped collar made of non-magnetic material between the stator core and the valve body (See Patent Document 1).

Here, the stator core and the valve body are integrated by welding or the like via a collar, and the surface of the integrated member facing the armature is cut. Since the corner formed by the stator core and the collar has an R, by chamfering the outer peripheral corner of the armature, the corner between the R and the outer peripheral corner of the armature is prevented from being buffered. ing.
JP 2007-132337 A

  However, the above-described conventional solenoid valve has a problem in that the magnetic flux leaks at the outer peripheral corner portion (that is, the chamfered portion) of the armature because the distance from the stator core becomes longer.

  In view of the above points, an object of the present invention is to reduce magnetic flux leakage at an outer peripheral corner of an armature.

  In order to achieve the above object, according to the first aspect of the present invention, the stator core (86) and the valve body (80) are coupled to each other at the end of the stator core (86) on the armature (83) side. ) And a ring-shaped collar (87) that restricts the flow of magnetic flux between the valve body (80) and the end of the stator core (86) on the armature (83) side is fitted inside the collar (87). In addition, a part of the inner peripheral surface of the collar (87) is opposed to the outer peripheral surface of the armature (83), and among the inner peripheral surfaces of the collar (87), the stator core (86) in the collar (87). ) And a concave portion (870) recessed in the radially outward direction is continuously formed between the portion fitted with the outer peripheral surface of the armature (83) in the collar (87). It is characterized in that is.

  According to this, since the concave portion (870) is formed on the inner peripheral surface of the collar (87), chamfering of the outer peripheral corner portion of the armature (83) becomes unnecessary, and the outer peripheral corner portion of the armature (83) and the stator core (86). Since the distance between the coil and the coil (90) is shortened, the magnetic flux leakage at the part can be reduced and the response when the coil (90) is energized can be improved.

  According to a second aspect of the present invention, in the electromagnetic valve according to the first aspect, the collar (87) is a portion where the inner diameter of the portion where the stator core (86) is fitted faces the outer peripheral surface of the armature (83). The inner diameter of the portion facing the outer peripheral surface of the armature (83) in the valve body (80) and the inner diameter of the portion facing the outer peripheral surface of the armature (83) in the collar (87) are set to be larger than the inner diameter of the armature (83). Are set equal to each other.

  According to this, without changing the clearance dimension between the inner peripheral surface of the valve body (80) and the outer peripheral surface of the armature (83), the area of the surface facing the armature (83) in the stator core (86) is increased and sucked. The force can be increased, and the responsiveness when the coil (90) is energized can be further improved.

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

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
A first embodiment of the present invention will be described. FIG. 1 is a diagram showing an overall configuration of a pressure accumulation fuel injection device including an electromagnetic valve according to a first embodiment of the present invention.

  As shown in FIG. 1, the fuel injection system includes a pressure accumulator 1 in which high-pressure fuel is stored. The pressure accumulator 1 is an injector provided for each cylinder of an internal combustion engine (more specifically, a diesel engine) (not shown). 2 is connected. The injector 2 is controlled by an electronic control unit (hereinafter referred to as ECU) (not shown), opens at a predetermined time for a predetermined period, and injects high-pressure fuel supplied from the accumulator 1 into each cylinder of the internal combustion engine. To do.

  The high pressure fuel stored in the pressure accumulator 1 is supplied from the fuel supply means. The fuel supply means includes a high pressure pump 3 that pressurizes the fuel and discharges it to the accumulator 1, a low pressure pump 5 that supplies the fuel sucked from the fuel tank 4 to the high pressure pump 3, and the low pressure pump 5 to the high pressure pump 3. An intake metering valve 6 for adjusting the flow rate of the supplied fuel is provided. The high-pressure pump 3 is a type of pump in which the fuel discharge amount is adjusted by adjusting the fuel intake amount by the intake metering valve 6.

  The pressure accumulator 1 is connected to the fuel tank 4 via a leak pipe 7. Further, a pressure reducing valve 8 as an electromagnetic valve that opens and closes a discharge flow path from the inside of the pressure accumulator 1 to the leak pipe 7 is attached to one end side in the longitudinal direction of the pressure accumulator 1. The pressure reducing valve 8 is controlled by the ECU according to the operating state of the internal combustion engine, and returns the high pressure fuel in the pressure accumulator 1 to the fuel tank 4 through the discharge flow path when the valve is opened, thereby setting the pressure of the pressure accumulator 1 to the target. To a value.

  The ECU includes a known microcomputer including a CPU, a ROM, a RAM, and the like (not shown), and performs arithmetic processing according to a program stored in the microcomputer. A signal from a fuel pressure sensor 9 that detects the pressure in the accumulator 1 is input to the ECU, and various information such as an engine speed and an accelerator opening is input from various sensors as needed. Based on the information, the operation of the injector 2, the suction metering valve 6, and the pressure reducing valve 8 is controlled.

  Next, the pressure reducing valve 8 will be described. 2 is a cross-sectional view showing the configuration of the pressure reducing valve 8 of FIG. 1, and FIG. 3 is an enlarged cross-sectional view of a portion A of FIG.

  The pressure reducing valve 8 includes a cylindrical valve body 80 made of a magnetic metal and fastened to the pressure accumulator 1 (see FIG. 1). The valve body 80 forms a magnetic circuit. The valve body 80 includes a cylindrical first cylindrical portion 800 and a cylindrical second cylindrical portion 801 having an inner diameter larger than the inner diameter of the first cylindrical portion 800. Are formed continuously in the axial direction. A spherical ball valve 81, a cylindrical valve rod 82, and a cylindrical armature 83 are accommodated in the first tube portion 800. A cylindrical guide 84 that slidably supports the valve rod 82 is inserted into the first tube portion 800. The armature 83 is made of a magnetic metal (for example, 3LSS) and forms a magnetic circuit. The valve stem 82 and the armature 83 are joined by press-fitting or welding.

  A valve seat 85 is fixed to the end of the first tube portion 800 by caulking or press-fitting. A tapered seat surface 850 is formed on the valve seat 85, and a ball valve 81 that contacts and separates from the seat surface 850 is disposed between the seat surface 850 and the valve rod 82.

  In the second cylindrical portion 801, a stator core 86 made of a magnetic metal (for example, 3LSS) that forms a magnetic circuit is disposed so as to face the armature 83. Then, the valve body 80 and the stator core 86 are hermetically joined by welding or brazing through a ring-shaped collar 87 made of a nonmagnetic metal (for example, SUS303) at the end of the stator core 86 on the armature 83 side. Has been.

  The collar 87 restricts the flow of magnetic flux between the valve body 80 and the stator core 86. More specifically, a part of the inner peripheral surface of the collar 87 faces the outer peripheral surface of the armature 83, Bypassing the armature 83, the magnetic flux flowing between the valve body 80 and the stator core 86 is suppressed.

  The stator core 86 has a bottomed cylindrical shape having a spring accommodating hole 860, and a spring 88 and a spring seat 89 are disposed in the spring accommodating hole 860. The ball valve 81, the valve rod 82, and the armature 83 are urged toward the valve seat 85 by the spring 88. Further, when the armature 83 is attracted to the stator core 86 side, the valve rod 82 comes into contact with the spring seat 89, so that the movement range of the valve rod 82 and the armature 83 to the stator core 86 side is restricted.

  A cylindrical coil 90 that forms a magnetic field when energized is disposed in the second cylindrical portion 801 and on the outer peripheral side of the stator core 86. In addition, a plate 91 made of a magnetic metal (for example, 3LSS) that forms a magnetic circuit is provided at the end of the second cylindrical portion 801.

  A first space 92 formed between the armature 83 and the guide 84 is connected to the inside of the pressure accumulator 1 by a through hole 851 formed in the valve seat 85. Further, the first space 92 is connected to the leak pipe 7 via a through hole 840 formed in the guide 84, a through hole 800 a formed in the first cylindrical portion 800, and a through hole (not shown) of the pressure accumulator 1. (See FIG. 1).

  A second space 93 defined by the guide 84 and the valve seat 85 communicates with the first space 92 through a gap between the first tube portion 800 and the guide 84. The spring housing hole 860 and the second space 93 communicate with each other through a groove 890 formed in the spring seat 89 and a communication hole 820 formed in the valve rod 82.

  The first shim 94 disposed between the guide 84 and the valve seat 85 adjusts the air gap between the armature 83 and the stator core 86 when the coil 90 is de-energized. ing.

  An air gap between the armature 83 and the stator core 86 when the coil 90 is energized and the armature 83 is attracted to the stator core 86 side by the second shim 95 disposed between the stator core 86 and the spring seat 89. Has been adjusted.

  A set load of the spring 88 is adjusted by a third shim 96 disposed between the spring 88 and the spring seat 89.

  Here, the joining of the valve body 80, the stator core 86, and the collar 87, and the subsequent cutting will be described in detail. On the outer peripheral surface of the stator core 86, a core outer peripheral small diameter portion 861 is formed on the armature 83 side, and a core outer peripheral large diameter portion 862 having an outer diameter larger than the outer diameter of the core outer peripheral small diameter portion 861 is formed on the anti-armature side. . On the inner peripheral surface of the valve body 80, the inner diameter is larger than the inner diameter of the first cylinder part 800 at the boundary between the first cylinder part 800 and the second cylinder part 801. A small fitting hole 802 is formed.

  The core outer peripheral small diameter portion 861 is fitted inside the collar 87, the collar 87 is fitted into the fitting hole 802, and the valve body 80, the stator core 86, and the collar 87 are joined by welding or the like, and then the valve body is joined. The surface of the stator core 86 facing the armature 83, the surface of the stator core 86 facing the armature 83, and the surface of the collar 87 facing the armature 83 (that is, the inner peripheral surface of the collar 87) are cut. In this cutting process, a concave portion 870 that is recessed radially outward is continuously formed in the inner peripheral surface of the collar 87 in the circumferential direction. The recess 870 is formed between a portion of the collar 87 where the stator core 86 is fitted and a portion of the collar 87 facing the outer peripheral surface of the armature 83.

  In the accumulator fuel injection device having the above-described configuration, the energization to the coil 90 of the pressure reducing valve 8 is cut off except when the internal combustion engine is decelerated. The ball valve 81 is urged toward the seat 85 and the ball valve 81 abuts against the seat surface 850 of the valve seat 85 to close the through hole 851.

  On the other hand, when the depression amount of the accelerator pedal is suddenly reduced, that is, when the internal combustion engine is decelerated, the ECU opens the pressure reducing valve 8, thereby discharging the high-pressure fuel in the pressure accumulator 1 to the fuel tank 4, The pressure in the vessel 1 is rapidly reduced to the target value.

  Specifically, when the coil 90 is energized and a suction force is generated between the stator core 86 and the armature 83, the valve rod 82 and the armature 83 are moved toward the stator core 86 against the spring force of the spring 88. Displace. Then, the ball valve 81 is pushed by the pressure of the high pressure fuel in the pressure accumulator 1, the ball valve 81 is separated from the seat surface 850 of the valve seat 85, and the through hole 851 of the valve seat 85 is opened. Thereby, the high-pressure fuel in the pressure accumulator 1 is fueled via the through hole 851 of the valve seat 85, the through hole 840 of the guide 84, the through hole 800a of the valve body 80, the through hole of the pressure accumulator 1, and the leak pipe 7. It is discharged into the tank 4.

  In the pressure reducing valve 8 of the present embodiment, since the recess 870 is formed on the inner peripheral surface of the collar 87, chamfering of the outer peripheral corner of the armature 83 on the stator core 86 side becomes unnecessary, and the outer peripheral corner of the armature 83 and the stator core are eliminated. Since the distance between the coil 86 and the coil 86 is shortened, magnetic flux leakage at that portion can be reduced, and the response when the coil 90 is energized can be improved.

(Second Embodiment)
A second embodiment of the present invention will be described. FIG. 4 is a cross-sectional view showing a main part of a solenoid valve according to the second embodiment of the present invention. In this embodiment, the configuration of the collar 87 is changed, and the other parts are the same as those in the first embodiment, and therefore only different parts will be described.

  As shown in FIG. 4, the collar 87 has a substantially L-shaped cross section in a plane parallel to the axis of the collar 87 and passing through the axis of the collar 87. More specifically, a collar inner peripheral large diameter portion 871 is formed on the stator core 86 side on the inner peripheral surface of the collar 87, and the inner diameter of the collar 87 is smaller than the inner diameter of the collar inner peripheral large diameter portion 871 on the anti-stator core side. A small diameter portion 872 is formed.

  The collar inner periphery large diameter portion 871 is fitted with the core outer periphery small diameter portion 861, and the collar inner periphery small diameter portion 872 faces the outer peripheral surface of the armature 83. The inner diameter of the portion of the first cylindrical portion 800 that faces the outer peripheral surface of the armature 83 and the inner diameter of the collar inner peripheral small diameter portion 872 are set equal. Here, assuming that the outer diameter of the core outer peripheral small diameter portion 861 is φD1 and the outer diameter of the armature 83 is φD2, the collar 87 is substantially L-shaped so that φD1> φD2.

  The concave portion 870 is formed by cutting after the valve body 80, the stator core 86, and the collar 87 are joined. The recess 870 is formed between the collar inner circumference large diameter portion 871 and the collar inner circumference small diameter portion 872.

  In the present embodiment, since the collar 87 is substantially L-shaped, the surface facing the armature 83 in the stator core 86 without changing the gap dimension between the inner peripheral surface of the first cylindrical portion 800 and the outer peripheral surface of the armature 83. Can be increased by increasing the area (that is, the area within φD1), and the responsiveness when the coil 90 is energized can be further improved.

It is a figure which shows the whole structure of the pressure accumulation type fuel injection apparatus provided with the solenoid valve which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the structure of the pressure reducing valve 8 of FIG. It is an expanded sectional view of the A section of FIG. It is sectional drawing which shows the principal part of the solenoid valve which concerns on 2nd Embodiment of this invention.

Explanation of symbols

80 Valve body 83 Armature 86 Stator core 87 Color 90 Coil

Claims (2)

A cylindrical coil (90) that forms a magnetic field when energized;
A stator core (86) disposed on the inner peripheral side of the coil (90) to form a magnetic circuit;
An armature (83) attracted to the stator core (86) by a magnetic attraction force;
A tubular valve body (80) disposed on the outer peripheral side of the armature (83) to form a magnetic circuit;
The stator core (86) and the valve body (80) are coupled at an end of the stator core (86) on the armature (83) side, and between the stator core (86) and the valve body (80). A ring-shaped collar (87) that restricts the flow of magnetic flux of
An end portion of the stator core (86) on the armature (83) side is fitted inside the collar (87), and a part of an inner peripheral surface of the collar (87) is an outer periphery of the armature (83). Facing the surface,
Further, of the inner peripheral surface of the collar (87), a portion of the collar (87) where the stator core (86) is fitted and a portion of the collar (87) facing the outer peripheral surface of the armature (83). A recess (870) recessed radially outward is continuously formed in the circumferential direction between the two. The collar (87) is set such that an inner diameter of a portion into which the stator core (86) is fitted is set larger than an inner diameter of a portion facing the outer peripheral surface of the armature (83).
An inner diameter of a portion of the valve body (80) facing the outer peripheral surface of the armature (83) is set equal to an inner diameter of a portion of the collar (87) facing the outer peripheral surface of the armature (83). The electromagnetic valve according to claim 1.

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