JP2006316965A - Solenoid valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solenoid valve capable of preventing the intrusion of foreign matters to a depth portion of a valve case, and securing the stable sliding performance and responsiveness of a spool valve. <P>SOLUTION: This solenoid valve comprises the valve case 2 having a sliding hole 21 formed in the axial direction and an outflow-side port 22 opened on the way of the sliding hole, the spool valve 1 slidably stored in the valve case and controlling a flow rate of a fluid, and a solenoid coil 4 axially moving the spool valve by a magnetomotive force by power distribution, and a filter device 6 is mounted to prevent the intrusion of foreign matters to a second internal flow channel 12 in of the spool valve. The filter device 6 is composed of a guide body 61, a filter 62 and a spring 63, and has a fail-safe function. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a solenoid valve that regulates a fluid flow rate, and more particularly to an electromagnetic suction regulator that is assembled in a fuel supply pump of a common rail fuel injection system and regulates the amount of fuel sucked into a pressurized chamber from a feed pump. It is suitable for application to a quantity valve.

  Conventionally, for example, in a common rail fuel injection system known as a fuel injection system for diesel engines, high pressure fuel is accumulated in the common rail, and the high pressure fuel accumulated in the common rail is mounted corresponding to each cylinder of the internal combustion engine. Further, it is configured to inject and supply the fuel into the combustion chamber of each cylinder of the internal combustion engine at a predetermined timing via a plurality of injectors. Since the high pressure fuel corresponding to the fuel injection pressure needs to be constantly stored in the common rail, the high pressure fuel is supplied from the fuel supply pump that pressurizes the fuel sucked into the pressurizing chamber through the electromagnetic valve and increases the pressure. Is discharged into the common rail.

  Here, the amount of fuel discharged from the fuel supply pump is adjusted by adjusting the opening area of the fuel intake path from the feed pump to the pressurizing chamber via the suction valve, and sucked into the pressurizing chamber from the feed pump. The amount of fuel to be applied is adjusted according to the pump drive current to the solenoid coil of the solenoid valve. As such an electromagnetic valve, a spool valve having both a valve body function for changing the opening area of the flow path by sliding in the sliding hole and an armature function for forming a magnetic path, and this spool valve An electromagnetic suction metering valve including a valve case having both a cylinder function for slidably accommodating and a stator function for forming a magnetic path is known from Patent Document 1 and the like.

JP 2002-106740 A

  In such an electromagnetic valve having a sliding portion in which the spool valve slides in the valve case, it is important to prevent foreign matter from getting caught in the sliding portion. Conventionally, a fuel purifier is provided in the fuel supply system, but minute foreign matter that cannot be removed by this conventional purifier enters the electromagnetic valve, and the sliding resistance of the sliding portion increases. There is a risk of malfunction. Such an increase in sliding resistance deteriorates the responsiveness of the spool valve, lowers the metering performance of the solenoid valve, and affects engine characteristics such as acceleration. In particular, since foreign matter tends to stay in the back of the valve case, it is necessary to prevent foreign matter from entering the back of the valve case.

  The present invention has been made in view of the above problems, and its purpose is to prevent foreign matter from entering the inner part of the valve case of the solenoid valve and to ensure stable slidability and responsiveness of the spool valve. It is to provide a solenoid valve that can.

The present invention provides an electromagnetic valve according to each of the claims as means for solving the problems.
The solenoid valve according to claim 1 includes a sliding hole 21 formed in the axial direction, an inflow side port 21 a through which fluid flows into the sliding hole 21, and an outflow side through which fluid flows out of the sliding hole 21. A valve case 2 having a port 22; a spool valve 1 which is accommodated in the valve case 2 so as to be slidable in a reciprocating manner; and a solenoid coil which moves the spool valve 1 in the axial direction by a magnetomotive force generated by energization. 4 and provided with a filter device 6 for preventing foreign matter from entering inside the spool valve 1 or upstream of the inflow side port 21a, whereby foreign matter enters the back of the electromagnetic valve. As a result, stable slidability and responsiveness of the spool valve 1 can be ensured.

  The electromagnetic valve according to claim 2 is such that the position where the filter device 6 is installed is the front part of the sliding hole 21 of the valve case 2 which is the fluid inflow side port 21a, and the electromagnetic valve according to claim 3 Is installed in the inflow path (71) of the pump housing (7) connected to the inflow side port 21a of the solenoid valve at the position where the filter device 6 is installed. As in the first aspect, stable slidability and responsiveness of the spool valve can be ensured.

  In the electromagnetic valve according to claim 4, the filter device 6 includes a cylindrical guide body 61 having an inflow port 61a and an outflow port 61b, and a filter (62) disposed in the guide body 61 so as to be movable in the axial direction. And a spring (63) disposed in the guide body 61 and biasing the filter 62 in the direction of closing the inflow port 61a. When the filter 62 receives a predetermined pressure or more, the filter 62 is The fluid moves and bypasses the filter 62 so as to flow into the back of the valve case 2, so that when the filter 62 is completely clogged when the spool valve 1 is opened, the back of the valve case 2 It is possible to solve the problem that the port cannot be closed because the fuel cannot move to the part and the spool valve 1 does not return.

  Hereinafter, solenoid valves according to embodiments of the present invention will be described with reference to the drawings. The solenoid valve of the present invention is preferably used in a common rail fuel injection device for a diesel engine, and its outline is configured as follows. The fuel supply pump sucks low-pressure fuel from the fuel tank, increases the pressure of the low-pressure fuel, and then pumps it to the common rail. The common rail accumulates fuel having a high predetermined pressure corresponding to the fuel injection pressure. The fuel supply pump is, for example, a three-system pressure feed pump having three pressure chambers, and controls the fuel discharge amount of the three systems by a flow rate control solenoid valve disposed in the fuel suction portion. The fuel pressure in the common rail is controlled by a known electronic control unit (ECU), and the discharge amount of the fuel supply pump is determined so that the common rail pressure becomes an optimum value, and the drive of the solenoid valve is controlled accordingly. It has become so. Thus, the high-pressure fuel accumulated in the common rail is injected and supplied into the combustion chamber of each cylinder of the engine via a plurality of injectors (electromagnetic fuel injection valves) mounted corresponding to each cylinder of the engine. Yes.

  FIG. 1 is a longitudinal sectional view of a solenoid valve according to an embodiment of the present invention. The solenoid valve is a spool valve 1 that adjusts a flow path opening area of a sleeve-like valve case 2 fixed to a pump housing 7 (see FIG. 5) and an outlet-side port 22 opened in the radial direction of the valve case 2. And a linear solenoid actuator A that drives the spool valve 1 in the valve opening direction, and a return spring 3 that urges the spool valve 1 in the valve closing direction.

  This solenoid valve is electronically controlled by a pump drive current applied from the ECU via a pump drive circuit (not shown), thereby adjusting the amount of fuel sucked into a pressurized chamber of a fuel supply pump (not shown). This is a normally closed electromagnetic flow control valve. That is, the solenoid valve is provided in the middle of the fuel intake path by moving the spool valve 1 in the stroke direction in proportion to the magnitude of the pump drive current applied to the linear solenoid actuator A via the pump drive circuit. The flow path opening area of the outlet side port 22 of the valve case 2 is adjusted. As a result, the amount of fuel sucked into the pressurizing chamber from the feed pump through the fuel suction path and the suction valve is adjusted. Therefore, the amount of fuel discharged from the pressurized chamber of the fuel supply pump into the common rail (not shown) is an optimum value corresponding to the engine operating conditions (for example, engine speed, accelerator operation amount, command injection amount, etc.). The fuel pressure in the common rail corresponding to the injection pressure of the fuel supplied from the injector to the combustion chamber of each cylinder of the engine, that is, the so-called common rail pressure is changed.

  The linear solenoid actuator A includes a bottomed cylindrical stator portion (stator core) 23 integrally provided at the right end portion of the valve case 2 in the figure, and an armature portion (armature portion) integrally provided at the right end portion of the spool valve 1 in the figure. 11) Resin coil bobbin 41 held on the outer periphery of the cylindrical portion of stator portion 23, solenoid coil 4 wound around the outer periphery of coil bobbin 41, and the terminal lead wire of solenoid coil 4 are electrically connected Terminal 42, a cylindrical housing 43 covering the outer peripheral side of the solenoid coil 4, and the like. Note that the stator portion 23 of the valve case 2 is magnetized when the solenoid coil 4 is energized to become an electromagnet, and has a suction portion 23 a for sucking the armature portion 11 of the spool valve 1. The suction portion 23a is connected to a substantially cylindrical housing portion 24 that slidably houses the spool valve 1 via a cylindrical thin portion 23c and a cylindrical portion 23b.

  The solenoid coil 4 generates a magnetomotive force when energized to magnetize the stator portion 23 of the valve case 2 and the armature portion 11 of the spool valve 1, thereby causing the armature portion 11 to move in the stroke direction (right side in the axial direction). The coil is a coil in which the coil bobbin 41 is wound a plurality of times with a conductive wire coated with an insulating film. The solenoid coil 4 has a coil portion wound between a pair of flange portions of the coil bobbin 41 and a pair of terminal lead wires taken out from the coil portion. The housing 43 is integrally formed of a resin material having excellent electrical insulation, and includes a cylindrical portion that covers the outer peripheral side of the solenoid coil 4 and a cylindrical connector portion 43 a that holds the terminal 42. On the outer periphery of the housing 43, a cylindrical bracket 44 fixed to the substantially annular flange portion formed on the outer peripheral side of the valve case 2 by means of caulking or the like is provided. A substantially annular flange portion 44a formed on the outer peripheral side of the bracket 44 is fastened and fixed to the outer wall surface of the pump housing 7 of the fuel supply pump using a fastener such as a bolt.

  The valve case 2 of the electromagnetic valve includes an accommodating portion 24 having a cylinder function for slidably accommodating the spool valve 1 and a stator portion 23 having a stator function for forming a magnetic path. In order for the valve case 2 to function as a stator, the material thereof is a soft magnetic material such as ferritic stainless steel (SUS13). Since this soft magnetic material deteriorates magnetic properties, it cannot be subjected to heat treatment such as quenching. However, in order for the valve case 2 to have a cylinder function, which is an original function, it is required to improve wear resistance and surface hardness. Therefore, the sliding hole (spool hole) 21 of the valve case 2 is required. A hardened layer such as nickel phosphorous plating is applied to the inner wall surface. The inner wall surface of the sliding hole 21 of the valve case 2 constitutes a cylindrical guide portion that guides the spool valve 1 in the axial direction (stroke direction).

  The illustrated left end portion of the valve case 2 is press-fitted into a fitting recess 73 (see FIG. 5) provided on the outer wall surface of the pump housing 7 of the fuel supply pump. A sealing material 8 such as an O-ring for preventing fuel leakage is mounted between the inner wall surface of the valve case 2 and the outer peripheral surface of the valve case 2 at the left end in the figure. An inlet-side port (inflow port) 21a that communicates with a fuel reservoir portion into which fuel is fed from a feed pump is formed at the left end portion of the valve case 2 in the figure. It should be noted that the outlet port (outlet port) 22 of the valve case 2 has four ports toward the communication passage 72 that constitutes the second half of the fuel suction path that communicates with the two pressurizing chambers via the two suction valves. It is open. The inlet side of the outlet side port 22 has a smaller flow path diameter than the outlet side. In addition, an internal flow communicating with the inlet port 21a via an internal flow path (second internal flow path) 12 formed in the spool valve 1 is provided on the right side of the sliding hole 21 of the valve case 2 in the figure. A path (first internal flow path) 25 is formed. The first internal flow path 25 also functions as a spring chamber that houses the return spring 3.

  The spool valve 1 of the solenoid valve is a sleeve-like spool type valve having a second internal flow path 12 in the inner axial direction, and is slidably in contact with the inner wall surface of the slide hole 21 of the valve case 2 on its outer peripheral surface. A moving part 13 is provided. The spool valve 1 is configured such that the sliding portion 13 changes the flow path opening area of the outlet port 22 of the valve case 2 so that the flow rate of fuel sucked into the two pressurization chambers via the two suction valves ( Fuel intake amount) is metered. The spool valve 1 slides in the sliding hole 21 of the valve case 2 to change the valve opening area of the outlet port 22 and an armature function (armature portion) for forming a magnetic path. 11). In order for the spool valve 1 to function as an armature, the material thereof is a soft magnetic material such as pure iron or low carbon steel. Since this soft magnetic material deteriorates magnetic properties, it cannot be subjected to heat treatment such as quenching. However, in order to function as the spool valve 1, improvement in wear resistance and improvement in surface hardness are required. Therefore, a hardened layer such as nickel phosphorous plating is applied to the outer peripheral surface of the sliding portion 13 of the spool valve 1.

  The spool valve 1 has an initial position defined by an annular retaining ring (stopper) 5 that is press-fitted and fixed to the inner periphery of the left end of the valve case 2 in the figure. The spool valve 1 is always urged by the return spring 3 accommodated in the first internal flow path 25. For this reason, the range of movement of the spool valve 1 on the valve closing side is defined at a position where the tip of the spool valve 1 contacts the retaining ring 5. Further, a cylindrical armature portion 11 provided integrally with the stator portion 23 of the valve case 2 via a predetermined air gap is integrally formed at the right end portion of the spool valve 1 in the figure. Further, a second internal flow path 12 is provided in the spool valve 1 so as to communicate the inlet side port 21 a of the valve case 2 and the first internal flow path 25. The inner diameter of the second inner flow path 12 is smaller on the right side in the figure than on the left side in the figure. When the spool valve 1 moves in the axial direction, the fuel in the first inner flow path 25 is taken in and out. Thus, the spool valve 1 can be easily moved.

  An annular metering groove (annular flow path) 14, an annular centering groove 15, and a plurality of annular oil grooves 16 are formed on the outer peripheral surface of the sliding portion 13 of the spool valve 1. The metering groove 14 is provided in the circumferential direction of the sliding portion 13, and communicates with the second internal channel 12 through a communication hole 17 having a smaller channel diameter than the metering groove 14. Four communication holes 17 are opened toward the metering groove 14. The alignment groove 15 is shallower than the adjustment groove 14 and is longer in the axial direction than the adjustment groove 14 and is provided in the circumferential direction of the sliding portion 13. The plurality of annular oil grooves 16 penetrates between the illustrated left end portion (tip portion) or right end portion (rear end portion) of the spool valve 1 and the sliding hole 21 of the valve case 2 so that the valve It is a circumferential groove portion that forms an oil film between the inner wall surface of the sliding hole 21 of the case 2 and the outer peripheral surface of the sliding portion 13 of the spool valve 1.

  Next, features of the present embodiment will be described. In the present embodiment, a filter device 6 is installed inside the spool valve 1. That is, the filter device 6 is provided on the right side of the drawing with respect to the position of the communication hole 17 in the second internal flow path 12 of the spool valve 1. As a result, foreign matter mixed in the fuel can be prevented from entering the first internal flow path 25 which is the inner part of the valve case 2, and stable sliding of the spool valve 1 can be ensured.

  3A and 3B are diagrams illustrating the overall configuration of the filter device 6, in which FIG. 3A is a diagram illustrating a state in which fuel cannot move due to clogging of the filter, and FIG. It is a figure explaining the state which can move now. In the present embodiment, the filter device 6 is provided with a valve function. That is, the filter device 6 includes a cylindrical guide body 61 having an inflow port 61a and an outflow port 61b, a filter 62 disposed in the guide body 61 so as to be movable in the axial direction, and a guide body 61. And a spring 63 that urges the filter 62 in a direction to close the inlet 61a. When the filter 62 is completely clogged, the spring 63 cannot move the fuel to the first internal flow path 25 of the valve case 2 as shown in FIG. In order to prevent the outlet side port 22 from being closed, an urging force that allows the filter 62 to move in a direction to open the inlet 61a when a pressure higher than a certain pressure is applied to the filter 62 as shown in FIG. 3B. Have. As a result, even if the filter 62 is clogged, the fuel can pass through the inlet 61a, bypass the filter 62, pass through the outlet 61b, and move to the first internal flow path 25. Returning, the exit side port 22 can be closed. In other words, the filter device 6 also has a fail-safe function in which when the abnormality occurs, the spool valve 1 is returned to close the outlet port 22 and can be safely stopped by shutting off the fuel.

  FIG. 2 is a cross-sectional view showing the operating state of the solenoid valve according to the present embodiment when the valve is closed (a) and when the valve is opened (b). When the solenoid coil 4 is not energized, the spool valve 1 is in a position where it abuts against a retaining ring (stopper) 5 by the urging force of the return spring 3 as shown in FIG. And the outlet side port 22 of the valve case 2 are in a position deviated from each other, and the outlet side port 22 is in a closed state (valve closed). The spool valve 1 is statically configured so that fuel pressure does not act in the sliding direction of the spool valve 1, and the spool valve 1 can be stably operated.

  When the solenoid coil 4 is energized, the spool valve 1 is displaced to the valve opening side against the urging force of the return spring 3 as shown in FIG. 2B, and the metering groove 14 of the spool valve 1 and the valve case The two outlet ports 22 communicate with each other. At this time, the movement range of the spool valve 1 on the valve opening side is restricted by the point that the force that the spool valve 1 is attracted to the stator portion 23 of the valve case 2 balances the urging force of the return spring 3. The displacement position of the spool valve 1 is determined by the energization amount of the solenoid coil 4, and when the energization amount is increased, the opening area of the communicating portion between the metering groove 14 and the outlet side port 22, that is, the flow path area is increased.

  FIG. 4 is a cross-sectional view of a solenoid valve according to another embodiment of the present invention. In the previous embodiment, the filter device 6 was installed inside the spool valve 1 of the electromagnetic valve. However, in this embodiment, the installation position is moved from the inside of the spool valve, and the front portion of the sliding hole 21 of the valve case 2 is moved. The filter device 6 is installed in the inflow side port 21a. Thereby, it is possible to completely prevent foreign matters mixed in the fuel from entering the electromagnetic valve. Since other configurations are the same as those in the previous embodiment, the description thereof is omitted.

  FIG. 5 is a sectional view of a solenoid valve according to still another embodiment of the present invention. In this embodiment, the installation place of the filter device 6 is the pump housing 7 of the fuel supply pump. That is, the pump housing 7 is provided with a fitting recess 73 for mounting the electromagnetic valve, and the electromagnetic valve is press-fitted and fitted therein. The fitting recess 73 communicates with an inflow path 71 and an outflow path 72 formed in the pump housing 7. When the electromagnetic valve is press-fitted into the fitting recess 73, the inflow path 71 and the outflow path 72 communicate with the inflow side port 21a and the outflow side port 22 of the electromagnetic valve, respectively. Therefore, in this embodiment, the filter device 6 is installed in the inflow path 71 of the pump housing 7. Even in this case, entry of foreign matter into the electromagnetic valve can be prevented.

  As described above, according to the present invention, it is possible to prevent the entry of minute foreign matter that cannot be removed by a conventional filter into the valve case, and to ensure stable slidability and responsiveness of the spool valve. It is possible to eliminate the influence on the engine characteristics such as acceleration. In addition, since the filter device has a fail-safe function, even when the filter is abnormal such as clogging, the spool valve can be returned to close the port and shut off the fuel, so that it can be safely stopped.

In the above description, a normally closed type (normally closed type) electromagnetic flow control valve that closes when the solenoid coil is not energized has been described. However, a normal valve that opens when the solenoid coil is not energized. An open type (normally open type) electromagnetic flow control valve may be used.
In addition, it is described as a solenoid valve used for a fuel supply pump of the intake fuel metering system of a common rail fuel injection system, but in addition to fuel, oil such as lubricating oil and hydraulic oil, liquid such as water, or air, It can also be used as appropriate as an electromagnetic flow control valve for adjusting the flow rate of gases such as exhaust gas and exhaust recirculation gas.

It is a longitudinal section showing the whole electromagnetic valve composition of an embodiment of the invention. It is sectional drawing which shows the operation state at the time of (a) valve closing and (b) valve opening of the solenoid valve of embodiment of this invention. It is a schematic diagram which shows the structure of a filter apparatus, (a) is a figure explaining the filter state at the time of abnormality, (b) is a figure explaining the filter apparatus which added the fail safe function. It is sectional drawing which shows the whole structure of the solenoid valve of another embodiment of this invention. It is sectional drawing which shows the whole structure of the solenoid valve of another embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Spool valve 11 Armature part 12 2nd internal flow path 13 Sliding part 14 Metering groove 2 Valve case 21 Sliding hole 21a Inflow side port 22 Outflow side port 23 Stator part 24 Storage part 25 1st internal flow path 3 Return spring 4 Solenoid coil 41 Coil bobbin 42 Terminal 5 Retaining ring (stopper)
6 Filter device 61 Guide body 62 Filter 63 Spring 7 Pump housing 71 Inflow path 73 Fitting recess

Claims (4)

A sliding hole (21) formed in the axial direction, an inflow port (21a) through which fluid flows into the sliding hole (21), and an outflow side through which fluid flows out of the sliding hole (21) A valve case (2) having a port (22);
A spool valve (1) accommodated in the sliding hole (21) of the valve case (2) so as to be slidable in a reciprocating manner;
A solenoid coil (4) that generates a magnetomotive force when energized and moves the spool valve (1) relative to the outflow side port (22) of the valve case (2) in the axial direction;
In a solenoid valve with
A filter device (6) is provided in the spool valve (1) or upstream of the inflow side port (21a) to prevent foreign matter from entering the inner part of the valve case (2). solenoid valve.   The electromagnetic device according to claim 1, wherein the filter device (6) is attached to a front portion of a sliding hole (21) of the valve case (2) which is a fluid inflow side port (21a). valve.   The electromagnetic device according to claim 1, wherein the filter device (6) is installed in an inflow path (71) of a pump housing (7) connected to an inflow side port (21a) of the electromagnetic valve. valve.   The filter device (6) is a cylindrical guide body (61) having an inflow port (61a) and an outflow port (61b), and a filter disposed in the guide body (61) so as to be movable in the axial direction. (62) and a spring (63) disposed in the guide body (61) and biasing the filter (62) in a direction to close the inlet (61a), When (62) receives a certain pressure or more, the filter (62) moves, and the fluid bypasses the filter (62) and flows into the back of the valve case (2). The electromagnetic valve according to claim 1, 2, or 3.

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