JP2006242108A - Solenoid valve and fuel injection device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solenoid valve of improved resistance against foreign matter and a fuel injection device using the same. <P>SOLUTION: The solenoid valve is provided with housings 11g, 16, 17 having a fluid passage and a valve seat formed thereon, an armature 40b provided with a valve element 40a opening and closing the fluid passage, an energizing member 38 energizing the armature 40b, a stator 31 including a storage hole 35c storing the energizing member 38 and a magnetic pole surface 31b, valve chambers 11e, 17b, 17c, 17d defined by the magnetic pole surface 31b and inner wall surfaces of the housing 11g, 16, 17 and storing the armature 40b, a discharge passage 53c discharging fluid to an outside when the armature 40b is attracted, and housings 33, 53 having communication holes 33d, 53d connecting the valve chambers 11e, 17b, 17c, 17d and the discharge passage 53c formed thereon. The storage hole 35c is shut off from the discharge passage 53c and the communication passages 33d, 53d. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a solenoid valve and a fuel injection device using the same.

  Conventionally, a solenoid valve is widely used in a fuel injection device that supplies fuel to an engine such as an internal combustion engine (Patent Document 1). As shown in FIG. 3, the electromagnetic valve of this document includes a stator 300 having a housing hole 310 and a magnetic pole surface 320 formed in a substantially central axis, and an armature disposed so as to face the magnetic pole surface 320. 400, a valve body 410 that moves in the same direction as the movement direction of the armature 400, and a spring 500 that is housed in the housing hole 350 and biases the armature 400 in the anti-suction direction. The electromagnetic valve is disposed between the first housing 100 in which the fluid passage 110 and the valve seat 120 are formed, and the second housing 200. A discharge passage 210 is formed in the second housing 200, and the discharge passage 210 is connected to the accommodation hole 310.

When the armature 400 is attracted to the magnetic pole surface 320 of the stator 300 and the valve body 410 is separated from the valve seat 120, the fluid flows into the space in which the armature 400 is accommodated via the fluid passage 110, and the accommodation hole. 310 and discharged to the outside of the solenoid valve through the discharge passage 210.
JP-A-5-133297

  However, according to the electromagnetic valve shown in FIG. 2, the fluid flowing into the space in which the armature 400 is accommodated through the fluid passage 110 is discharged to the outside of the electromagnetic valve through the accommodation hole 310 and the discharge passage 210. It has become. For this reason, in order for the fluid flowing into the space in which the armature 400 is accommodated to flow into the accommodation hole 310 formed in the substantially central axis, it must pass through the vicinity of the magnetic pole surface 320.

  If a foreign material such as a magnetic material is included in the fluid, the magnetic material is adsorbed by the magnetic force generated on the magnetic pole surface 320 and deposited near the magnetic pole surface 320. When a magnetic material is deposited on the magnetic pole surface 320, the distance between the armature 400 and the magnetic pole surface 320 is shortened, and the movement amount (lift amount) of the armature 400 is reduced. Further, when the magnetic material is deposited, there is a possibility that the armature 400 does not move even if the stator 300 tries to attract the armature 400.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a solenoid valve with improved foreign matter resistance and a fuel injection device using the same.

  In order to achieve the above object, according to the electromagnetic valve according to claim 1 of the present invention, a fluid passage is defined in the interior and a housing for accommodating the valve seat is provided, and a fluid is provided when seated on the valve seat. A valve body that closes the passage and opens the fluid passage when it is separated from the valve seat is provided in the housing, an armature that moves the valve body in the valve opening direction and the valve closing direction, and an armature that is provided in the housing and opens the armature. A stator having a magnetic pole surface that attracts in the valve direction; a biasing member that is disposed in a receiving hole provided in the stator and biases the armature in the valve closing direction; and is divided by the magnetic pole surface and the inner wall surface of the housing; A valve chamber that houses the armature, a discharge passage that is provided in the housing and discharges the fluid flowing into the valve chamber from the fluid passage when the armature is sucked by the magnetic pole surface; And a communication passage that is partitioned between the inner wall surface of the ring and the outer peripheral surface of the stator, one connected to the valve chamber and the other connected to the discharge passage, and the receiving hole is cut off from the discharge passage and the communication passage. It is characterized by being.

  According to this configuration, when the armature is attracted to the magnetic pole surface of the stator and the valve body is separated from the valve seat, the fluid once flows into the valve chamber. The valve chamber is connected to a communication passage defined between the inner wall surface of the housing and the outer peripheral surface of the stator, and the communication passage is connected to a discharge passage provided in the housing. For this reason, the fluid flowing into the valve chamber is discharged to the outside of the electromagnetic valve through the communication passage and the discharge passage. Since the accommodation hole in which the urging member is accommodated is not connected to the communication path and the discharge path, a fluid flow flows from the outer periphery of the armature into the accommodation hole through the space between the magnetic pole face of the stator and the armature. Not formed. Even if a foreign material made of a magnetic material is included in the fluid, the amount of fluid flowing in between the magnetic pole surface and the armature is reduced, so that it is deposited on the magnetic pole surface by the magnetic force generated on the magnetic pole surface. This can prevent the foreign matter resistance of the solenoid valve.

  According to the electromagnetic valve according to claim 2 of the present invention, the electromagnetic valve according to claim 1 is characterized in that the communication path has a portion inclined with respect to the axial direction of the accommodation hole.

  According to this configuration, when the discharge passage is formed substantially coaxially with the receiving hole, the flow of the communication passage connected to the discharge passage can be increased without increasing the size of the housing in which the discharge passage is formed. The road diameter can be increased.

  According to the electromagnetic valve according to claim 3 of the present invention, in the electromagnetic valve according to claim 1 or 2, the shim for adjusting the urging force of the urging member is provided at the bottom of the accommodation hole. It is characterized by being provided.

  According to this configuration, it is possible to adjust the urging force of the urging member by the shim even if the accommodation hole and the discharge passage are not connected.

  According to the fuel injection device of the fourth aspect of the present invention, the nozzle valve member that opens and closes the nozzle hole, and the pressure that supports the nozzle valve member so as to reciprocate and applies fuel pressure to the nozzle valve member in the nozzle hole closing direction. It has the nozzle main body in which the chamber is formed, The electromagnetic valve as described in any one of Claims 1-3 which controls the fuel pressure of a pressure chamber, It is characterized by the above-mentioned.

  Generally, a fuel injection device is assembled by screwing together a plurality of metal parts such as a nozzle valve member, a nozzle body, and a housing. The fuel injection device is supplied with fuel from the fuel pump, and controls the armature of the electromagnetic valve to control the fuel injection from the fuel pump and the fuel injection from the nozzle hole. In the fuel injection device, burrs (foreign matter) of parts when the parts are assembled remain, or fuel containing foreign matters made of metal (magnetic material) is supplied from the fuel pump.

  On the other hand, according to the above configuration, even if a fuel containing a metallic (magnetic material) foreign matter is introduced into the fuel injection device, the foreign matter made of the magnetic material contained in the fuel is prevented from contacting the magnetic pole surface of the stator. Since it is discharged from the discharge passage to the outside of the electromagnetic valve without passing through, it can be prevented from being deposited on the magnetic pole surface by the magnetic force generated on the magnetic pole surface, and the foreign matter resistance of the fuel injection device is improved.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an example specifically showing an embodiment of the present invention will be described with reference to the drawings. FIG. 2 shows an injector 1 as a fuel injection device according to an embodiment of the present invention. FIG. 1 is a cross-sectional view showing a portion related to a solenoid valve of an injector according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing an injector according to an embodiment of the present invention. The injector 1 is inserted and mounted in an engine head (not shown) of the engine, and is configured to inject fuel directly into each cylinder of the engine.

The lower body 11 and the nozzle body 12 are fastened by a retaining nut 14.
The lower body 11 and the nozzle body 12 constitute a nozzle body described in the claims. The lower body 11 has a needle accommodation hole 11d, and the nozzle body 12 has a needle accommodation hole 12e. A nozzle valve member 20 is accommodated in the needle accommodation holes 11d and 12e.

  A fuel inflow passage 11a is formed in the inlet portion 11f of the lower body 11, and a bar filter 13 is accommodated in the fuel inflow passage 11a. The fuel inflow passage 11a communicates with a fuel passage 12d formed in the nozzle body 12 through the fuel passage 11b. The fuel passage 12d communicates with the needle accommodation hole 12e in the fuel reservoir 12c. The needle accommodation hole 12e communicates with an in-cylinder space of the engine (not shown) through the injection hole 12b.

  Accordingly, fuel supplied by a fuel pump (not shown) is introduced into the injector 1 through the bar filter 13, and the engine is introduced through the fuel inflow passage 11a, the fuel passages 11b and 12d, the fuel reservoir 12c, the needle accommodation hole 12e, and the injection hole 12b. To each cylinder. Further, the lower body 11 is formed with a leak passage 11c communicating with the needle accommodation hole 11d.

  The nozzle valve member 20 includes a needle 20c, a rod 20b, and a control piston 20a from the nozzle hole 12b side. The needle 20c includes a seat portion, a small diameter portion, a tapered portion, and a large diameter portion from the nozzle hole 12b side. The large diameter portion is supported on the inner wall of the needle housing hole 12e so as to be reciprocally movable and almost liquid-tight. The seat portion is formed so as to receive pressure upward from FIG. 2 from the fuel. A gap in the circumferential direction is formed between the outer wall of the small diameter portion and the inner wall of the needle accommodation hole 12e.

  The seat portion has a shape that can be seated on the valve seat 12a. One end of the rod 20 b is in contact with the needle 20 c and the other end is in contact with the first spring 15. The first spring 15 biases the needle 20c to the valve seat 12a via the rod 20b. The control piston 20a is supported on the inner wall of the needle accommodation hole 11d so as to be reciprocally movable and substantially liquid-tight, and its lower end is in contact with the needle 20c.

  The part which concerns on the solenoid valve of the injector 1 is shown. As shown in FIG. 1, the first plate 16 is provided on the side opposite to the nozzle body of the needle accommodation hole 11d. The first plate 16 is formed with an out-orifice 16a communicating with the needle housing hole 11d and an in-orifice 16b communicating with the out-orifice 16a and the fuel inflow passage 11a. A pressure chamber 16c is formed by the outer wall of the end of the control piston 20a, the inner wall of the needle housing hole 11d, and the inner wall of the out orifice 16a.

  A second plate 17 is provided on the side opposite to the injection hole of the first plate 16. A valve seat 16d is formed in a planar shape on the end surface of the first plate 16 on the second plate side. A male screw is formed on the outer peripheral portion of the second plate 17, and the first plate 16 is sandwiched between the second plate 17 and the lower body 11 by being screwed into the cylindrical screw portion 11 g of the lower body 11. Has been. Through holes 17 a and 17 b are formed in the second plate 17. A conduction path 17d is formed between the through hole 17a and the through hole 17b.

  A valve chamber 17c is formed by the second plate side end surface of the first plate 16 and the inner wall of the through hole 17a. The out orifice 16a communicates the pressure chamber 16c and the valve chamber 17c. The out orifice 16a corresponds to the fluid passage described in the claims. The valve seat 16d corresponds to the valve seat recited in the claims.

  A gap 11e is formed in the circumferential direction between the outer wall of the first plate 16 and the inner wall of the lower body 11, and the gap 11e communicates with the through hole 17b of the second plate 17. The cylindrical thread portion 11g, the first plate 16, and the second plate 17 of the lower body 11 correspond to a part of the housing of the solenoid valve described in the claims. Further, the lower body 11 and the nozzle body 12 correspond to the nozzle body described in the claims.

  The stator 31 is accommodated in a cylindrical case 33. The inner diameter of the case 33 is large on the side opposite to the valve seat, and decreases as the conical inclined surface 33b approaches the valve seat 16d. A positioning flange 33 a is formed on the outer periphery of the case 33. On the inner wall of the body upper 52, a step surface 52a that contacts the positioning flange 33a is formed. When the body upper 52 is screwed into the cylindrical screw portion 11g formed at the end of the lower body 11, the positioning flange 33a is clamped between the body upper 52 and the cylindrical screw portion 11g together with the spacer 19, and the case 33 is lowered. 11 is fixed.

  The spacer 19 is an annular plate that adjusts the maximum lift amount of the control valve member 40 according to its thickness. Further, a disc spring is provided between the positioning flange 33a and the cylindrical screw portion 11g in place of the spacer 19, and the amount of lift of the control valve member 40 can be adjusted by adjusting the screwing amount of the body upper 52 after assembly. It can also be configured. The opening on the side opposite to the valve seat of the case 33 is closed by the housing 53, and the thin portion 33 c is sandwiched between the inner wall of the body upper 52 and the outer wall of the housing 53.

  A stopper member 35 is provided on the armature side end surface of the housing 53. The stopper member 35 is a cylinder composed of a buffer flange 35a and a cylinder portion 35b. An annular stator 31 is provided on the radially outer side of the cylindrical portion 35b. A predetermined minute circumferential clearance is formed between the inner wall surface 31a of the stator 31 and the outer wall surface of the stopper member 35, and the stator 31 and the stopper member 35 are not directly coupled. A spring chamber 35c is formed on the inner wall of the cylindrical portion 35b. The spring chamber 35c accommodates a second spring 38 as a biasing member that biases the control valve member 40 in the direction of the valve seat 16d. The spring chamber 35c corresponds to the accommodation hole described in the claims.

  The stator 31 has a large diameter portion, a tapered portion, and a small diameter portion from the buffer flange 35a side. The end surface of the large diameter portion is in contact with the buffer flange 35a, and the outer diameter of the large diameter portion and the outer diameter of the buffer flange 35a are substantially equal. The outer wall surface of the tapered portion is in contact with the conical inclined surface 33 b of the case 33. The end surface of the small diameter portion functions as the magnetic pole surface 31 b and faces the control valve member 40. A bobbin 34 and a coil 32 wound around the bobbin 34 are fixed to the small diameter portion with resin. The coil 32 is electrically connected to a terminal 51 extending to the connector 50. A gap 33 d is formed in the circumferential direction between the outer wall of the stator 31 and the inner wall of the case 33, and the gap 33 d communicates with the through hole 17 b of the second plate 17. The gap 11e, the through hole 17b, the valve chamber 17c, and the conduction path 17d correspond to the valve chamber described in the claims.

  The housing 53 is formed with a recess 53a communicating with the end surface on the stopper member side and a terminal accommodating hole 53b in the axial direction. The recess 53a communicates with the spring chamber 35c. The bottom of the recess 53a supports the second spring 38, and adjusts the force with which the second spring 38 biases the control valve member 40, the so-called set load. The shim 37 is provided.

  Further, the housing 53 is formed with a return passage 53c and a conduction passage 53d. The return passage 53c has an opening at the end surface on the side opposite to the stopper member of the housing 53, and is formed on the coaxial line of the recess 53a. The stopper member side of the return passage 53c does not communicate with the bottom of the recess 53a. The conduction path 53d is inclined with respect to the spring chamber 35c, one end of which is connected to the stopper member side end of the return path 53c, and the other end is connected to the gap 33d. A return pipe 54 is inserted into the opening of the housing 53. The case 33 and the housing 53 correspond to a part of the housing described in the claims. The gap 33d and the conduction path 53d correspond to the communication path described in the claims. The return passage 53c corresponds to the discharge passage described in the claims.

  The control valve member 40 includes a spherical member 40a and an armature 40b from the valve seat 16d side. The spherical member 40a and the armature 40b may be connected to each other by press-fitting or the like, may be formed integrally, or may be formed separately and in contact with each other. A recess 40c that supports one end of the second spring 38 is formed on the valve seat side of the armature 40b. The spherical member 40a corresponds to the valve body described in the claims.

  A part of the spherical member 40 a is formed in a planar shape that can close the out orifice 16 a by being seated on the valve seat 16 d of the first plate 16. The armature 40b is composed of a large diameter portion and a small diameter portion, and the small diameter portion is supported by the inner wall of the through hole 17a so as to be reciprocally movable. The large diameter portion is provided between the end face on the counter valve seat side of the second plate 17 and the magnetic pole surface 31 b of the stator 31.

  Next, the fuel injection operation of the injector 1 will be described. The fuel is discharged from a fuel injection pump (not shown) and sent to a pressure accumulating pipe (not shown). The high-pressure fuel accumulated at a predetermined pressure in the pressure accumulation chamber of the pressure accumulation pipe is supplied to the injector 1 through a pipe (not shown) connected to the inlet portion 11f. Further, a drive current corresponding to the engine operating condition is generated by an ECU (not shown) and supplied to the coil 32. When a drive current flows through the coil 32, an attractive force is generated on the magnetic pole surface 31b of the stator 31. When the force in the valve opening direction, which is the resultant force of the suction force and the force received from the fuel pressure in the pressure chamber 16c, exceeds the biasing force of the second spring 38, the armature 40b is attracted to the magnetic pole surface 31b.

  When the armature 40b is attracted to the magnetic pole surface 31b, the spherical member 40a moves together with the armature 40b in the valve opening direction, that is, upward in FIG. When the spherical member 40a opens the out orifice 16a, the pressure chamber 16c communicates with the low pressure side valve chamber 17c through the out orifice 16a, and fuel is led out from the pressure chamber 16c to the valve chamber 17c. The fuel led out to the valve chamber 17c returns from a pipe (not shown) to a fuel tank (not shown) through the conduction path 17d, the through hole 17b, the gap 33d, the conduction path 53d, the return path 53c, and the return pipe 54. The fuel flowing through the leak passage 11c returns from a pipe (not shown) to a fuel tank (not shown) through the gap 11e, the through hole 17b, the gap 33d, the conduction path 53d, the return path 53c, and the return pipe 54.

  When the pressure chamber 16c communicates with the valve chamber 17c, the fuel pressure in the pressure chamber 16c starts to decrease because the amount of fuel flowing out from the out orifice 16a is larger than the amount of fuel flowing in from the in orifice 16b. The injection hole opening direction in which the force in the injection hole closing direction, which is the resultant force of the biasing force of the first spring 15 and the force received from the fuel pressure in the pressure chamber 16c, is received from the fuel pressure in the fuel reservoir 12c when the fuel pressure in the pressure chamber 16c decreases. The needle 20c starts moving in the nozzle hole opening direction, that is, upward in FIG. 1, and moves away from the valve seat 12a. When the needle 20c is separated from the valve seat 12a, fuel is injected from the injection hole 12b.

  When the supply of the drive current to the coil 32 is interrupted, the attractive force generated on the magnetic pole surface 31b of the stator 31 disappears, so that the second spring 38 counteracts the force received from the fuel pressure in the pressure chamber 16c against the armature 40b. The spherical member 40a is moved in the valve closing direction. Even after the out-orifice 16a is closed by the spherical member 40a, the fuel continues to flow into the pressure chamber 16c from the in-orifice 16b, so that the fuel pressure in the pressure chamber 16c starts to rise. The fuel pressure in the pressure chamber 16c rises, and the force in the nozzle hole closing direction, which is the resultant force of the biasing force of the first spring 15 and the force received from the fuel pressure in the pressure chamber 16c, is received in the nozzle hole opening direction. When larger than the force, the needle 20c starts to move in the direction of closing the nozzle hole, that is, downward in FIG. When the needle 20c is seated on the valve seat 12a, the fuel injection is finished.

  According to the injector 1 according to the embodiment of the present invention, the spring chamber 35c and the recess 53d are not in communication with the gap 33d, the conduction path 53d, and the return path 53c, and therefore the fuel in the pressure chamber 16c and the gap 11e. Does not return to the fuel tank through the spring chamber 35c and the recess 53d, but returns from the pipe to the fuel tank through the through hole 17b, the gap 33d, the conduction path 53d, the return path 53c, and the return pipe 54, respectively. A flow of fuel flowing from the outer periphery of the armature 40b into the spring chamber 35c through the space between the magnetic pole surface 31b of the stator 31 and the armature 40b is not formed. As a result, even if foreign matter made of a magnetic material is contained in the fuel, the fuel passes through a path far from the magnetic pole surface 31b of the stator 31. Therefore, there is a problem with the electromagnetic valve used in the conventional fuel injection device. Thus, it is possible to prevent foreign matter from being deposited between the magnetic pole surface 320 and the armature 400 due to the magnetic force from the magnetic pole surface 320, and foreign matter resistance is improved.

  Further, according to the injector 1 according to the embodiment of the present invention, the return passage 53c is formed substantially coaxially with the spring chamber 35c, and the conduction path 53d is formed in the housing 53 so as to be inclined with respect to the spring chamber 35c. ing. Thereby, it becomes possible to make the flow path diameter of the conduction path 53d relatively large without increasing the size of the housing 53. As a result, the mountability of the injector 1 on the engine is not reduced.

  In addition, this makes it possible to relatively shorten the distance from the pressure chamber 16c or the gap 11e to the return pipe 54, thereby reducing the flow path resistance and allowing the fuel to quickly return to the fuel tank. .

  Generally, an injector needs to increase the fuel injection amount from the injection hole and the accuracy of the injection timing. In order to increase the accuracy, it is necessary to adjust the biasing force of the spring against the armature in addition to increasing the dimensional accuracy of the parts.

  Further, according to the injector 1 according to the embodiment of the present invention, since the shim 37 is provided at the bottom of the recess 53a formed in the housing 53, the second spring 38 biases the control valve member 40. The force, so-called set load, can be adjusted. As a result, the fuel injection amount from the injection hole and the accuracy of the injection timing can be improved.

It is sectional drawing which shows the part concerning the solenoid valve of the injector by one Embodiment of this invention. It is sectional drawing which shows the injector by one Embodiment of this invention. It is sectional drawing which shows the conventional solenoid valve.

Explanation of symbols

1 Injector 11 Lower body (nozzle body)
11e Clearance (valve chamber)
11g Tubular thread (housing)
12 Nozzle body (nozzle body)
16 First plate (housing)
16a Out orifice (fluid passage)
16b In-orifice 16c Pressure chamber 16d Valve seat (valve seat)
17 Second plate (housing)
17a Through hole 17b Through hole (valve chamber)
17c Valve chamber (valve chamber)
17d Conduction path (valve chamber)
31 Stator 31b Magnetic pole surface 33 Case (housing)
33d Clearance (communication path)
35c Spring chamber (receiving hole)
37 Shim 38 Second spring (biasing member)
40a Spherical member (valve)
40b Armature 53 Housing (housing)
53c Return passage (discharge passage)
53d Conduction path (communication path)
54 Return pipe

Claims (4)

A housing that defines a fluid passage therein and accommodates a valve seat;
A valve body that is provided in the housing, closes the fluid passage when seated on the valve seat, and opens the fluid passage when separated from the valve seat;
An armature provided in the housing and moving the valve body in a valve opening direction and a valve closing direction;
A stator provided in the housing and having a magnetic pole surface for attracting the armature in a valve opening direction;
An urging member disposed in an accommodation hole provided in the stator and urging the armature in a valve closing direction;
A valve chamber that is partitioned by the magnetic pole surface and the inner wall surface of the housing and that houses the armature;
A discharge passage that is provided in the housing and discharges the fluid flowing into the valve chamber from the fluid passage to the outside when the armature is attracted to the magnetic pole surface;
A communication passage that is partitioned between the inner wall surface of the housing and the outer peripheral surface of the stator, one connected to the valve chamber, and the other connected to the discharge passage;
The electromagnetic valve, wherein the accommodation hole is cut off from the discharge passage and the communication passage.   The electromagnetic valve according to claim 1, wherein the communication path has a portion that is inclined with respect to an axial direction of the accommodation hole.   3. The solenoid valve according to claim 1, wherein a shim for adjusting a biasing force of the biasing member is provided at a bottom portion of the accommodation hole. A nozzle valve member for opening and closing the nozzle hole;
A nozzle body that supports the nozzle valve member so as to be reciprocally movable, and a nozzle body in which a pressure chamber that applies fuel pressure to the nozzle valve member in a nozzle hole closing direction is formed;
A fuel injection device comprising: the electromagnetic valve according to any one of claims 1 to 3 that controls a fuel pressure in the pressure chamber.

Images