JP2006161568A - Control valve and fuel injection valve having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control valve easy to be assembled and reducing driving energy, without high machining accuracy or positioning accuracy. <P>SOLUTION: For boosting fuel supplied from a common rail 2 to a boosting device 4 by the drive of a boosting piston 44 and then injecting the boosted fuel from the injection nozzle 7, a hydraulic servo valve 3 for controlling boosting operation and injecting operation is provided. The hydraulic servo valve 3 of a two-position three-way valve increases/decreases hydraulic pressure of a servo valve control chamber 13 to make a boost control passage 14 and an injection control passage 15 selectively communicate with a return port 28 leading to a return passage 27 or a high pressure port 22 leading to the common rail 2. The hydraulic servo valve 3 is divided into an upper valve 31 provided with an upper seat 33 and a lower valve 32 provided with a lower seat 34 to be driven, so that its machining is facilitated and the driving energy is reduced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a control valve suitably used for a fuel injection valve of an internal combustion engine, for example. Specifically, the present invention relates to a control valve that controls a pressure increasing operation in a pressure increasing device provided in a fuel injection valve.

A common rail fuel injection system that supplies fuel from a common pressure accumulator (common rail) to fuel injection valves provided in each cylinder of an internal combustion engine has attracted attention. In recent years, it has been required to increase the fuel injection pressure for the purpose of increasing the output and improving the fuel efficiency and exhaust gas purification performance. It has been proposed (for example, Patent Document 1).
JP 2002-539372 A

  In general, a booster for a fuel injection valve pressurizes fuel supplied from a common rail with a booster piston to increase the injection pressure. As an example, for example, when the configuration of Patent Document 1 is shown in FIG. 5, the fuel in the fuel tank T pressurized by the high pressure pump P is accumulated in the common rail 10, and the fuel reservoir of the fuel injection valve 100 is accumulated from the common rail 10. A fuel of a predetermined pressure is supplied to 101. The pressure intensifier is disposed between the common rail 10 and the fuel reservoir 101, boosts the fuel supplied to the pressure increasing chamber 104 using the pressure increasing piston 103, and then supplies the fuel to the fuel reservoir 101. The driving of the booster piston 103 is controlled by increasing or decreasing the hydraulic pressure in the pressure chamber 106 using an electromagnetically driven booster control valve 105.

  The fuel of the common rail 10 is also supplied to the back pressure chamber 108 of the needle 109 that opens and closes the nozzle hole. When the injection control valve 107 is opened to lower the hydraulic pressure in the back pressure chamber 108, the needle 109 lifts and injects fuel in the common rail 10 or fuel increased in pressure by the pressure intensifier. By attaching such a pressure intensifying device, it is possible to perform injection at a higher pressure, and to perform a finer control according to the operation state, thereby realizing a desired injection rate.

Here, the pressure increasing control valve 105 for controlling the pressure increasing operation is a two-position three-way valve, and by selectively switching the seat position of the valve body, the pressure chamber 106 is selectively communicated with the common rail 10 or the return passage. The hydraulic pressure in the chamber 106 is increased or decreased. In general, a spool valve having a cylindrical seal portion and a valve having two tapered seat portions are used as a valve body of a two-position three-way valve. Patent Document 2 discloses a control valve in which a valve member is provided with a taper sheet and a pipe-like flat sheet for nozzle control of a fuel injection valve. If one of the valve seat portions is flat, there is an advantage that positioning accuracy during assembly is not required.
JP 2001-90634 A

  Generally, a control valve requires a large amount of driving energy when the seat diameter is increased in order to control a large flow rate. The three-way control valve provided with a taper seat and a pipe seat in one valve member proposed in Patent Document 2 attempts to reduce the drive energy by balancing the hydraulic pressure by making the upper and lower seat diameters the same. There is a need for precision machining to prevent leakage from the pipe seat. Furthermore, there is a problem that when the valve is closed, a valve opening force is generated by the oil film of the pipe seat, and a strong valve closing force is required to suppress it.

  Therefore, the present invention provides a high-performance and highly reliable control valve that does not require high processing accuracy and positioning accuracy, facilitates manufacture and assembly, and reduces drive energy. For the purpose.

  The control valve according to claim 1 is configured such that the second valve member is inserted and arranged inside the first valve member accommodated in the valve housing, and when the first valve member is seated on the first valve seat, the second valve member is The second port communicates with the control passage by being pushed by the first valve member and separated from the second valve seat. Further, when the second valve member is seated on the second valve seat, the first valve member is separated from the first valve seat and the first port communicates with the control passage. As described above, the control passage and the first port or the second port are selectively communicated.

  According to the present invention, since the three-way control valve is composed of two valve members each formed with a seat, high processing accuracy and positioning accuracy are not required. Accordingly, it is an object of the present invention to provide a valve device that can be easily manufactured and assembled, and simply has high performance and high reliability.

  The control valve according to claim 2 is configured such that the first valve member and the second valve member are closely arranged in the valve housing using a biasing member, and the second valve member has a second valve when the first valve member is seated on the first valve seat. The valve member is pushed by the first valve member and is separated from the second valve seat so that the second port communicates with the control passage. Further, when the second valve member is seated on the second valve seat, the first valve member is separated from the first valve seat and the first port communicates with the control passage. As described above, the control passage and the first port or the second port are selectively communicated.

  Also according to the present invention, since the three-way control valve is composed of two valve members each formed with a seat, high processing accuracy and positioning accuracy are not required. Accordingly, it is an object of the present invention to provide a valve device that can be easily manufactured and assembled, and simply has high performance and high reliability.

  In the control valve according to the third aspect, the control passage is disposed between the first valve seat and the second valve seat. Then, the first port is disposed on the opposite side of the control passage with respect to the first valve seat, and the second port is disposed on the opposite side of the control passage with respect to the second valve seat, whereby the control passage and the first port are disposed. Alternatively, the hydraulic pressure of the control passage can be switched by selectively communicating the second port.

  5. The control valve according to claim 4, wherein the first valve member slides in a cylinder provided in the valve housing, the seat diameter of the first valve member with respect to the sliding diameter of the first valve member, and the second valve member The seat diameter is reduced. Thereby, the oil pressure applied to the sliding diameter of the first valve member can be made larger than the oil pressure applied to the seat diameter, and the valve member is controlled by controlling the oil pressure applied to the sliding diameter of the first valve member. Can move.

  In the control valve according to claim 5, the second valve member does not have a sliding portion with respect to the valve housing and the first valve member. Therefore, the second valve member does not require highly accurate sliding processing.

  According to a sixth aspect of the present invention, the first valve seat and the second valve seat are provided on the inner periphery of the cylinder provided in the valve housing, and are arranged at different positions in the axial direction. As a result, the first valve member and the second valve member can be inserted from the direction facing the valve housing, respectively, and assembly is facilitated.

  According to a seventh aspect of the present invention, the first port communicates with the low pressure fluid passage and the second port communicates with the high pressure fluid passage, and the seat diameter of the first valve body and the seat diameter of the second valve body are equal. In this way, the fluid pressure acts to close the first valve body and open the second valve body with respect to the valve body. Safety can be increased.

  In the control valve according to claim 8, the first port communicates with the low pressure fluid passage, the second port communicates with the high pressure fluid passage, and the seat diameter of the first valve body is smaller than the seat diameter of the second valve body. If it does in this way, the pressure of a control room can be made into low pressure gently, and can be made high pressure quickly. Therefore, for example, when applied to a fuel injection valve, the valve opening speed of the nozzle needle can be reduced and the valve closing speed can be increased to make the injection rate a delta type, which is suitable for NOx reduction.

  The control valve according to claim 9 is provided with a hydraulic chamber surrounded by the sliding portion end surface of the first valve member and a cylinder inner wall surface provided in the valve housing, and the pressure in the hydraulic chamber is controlled by an electric actuator. One valve member is driven. In this way, the electric actuator can drive a control valve that requires a large force with a small force that controls the pressure in the hydraulic chamber.

  According to a tenth aspect of the present invention, there is provided a control valve in which a hydraulic chamber communicates with a high-pressure fluid passage through a first orifice, and a passage communicated with a low-pressure fluid passage through a valve body controlled by a second orifice and an electric actuator. Prepare. If it does in this way, the fuel which leaks from a hydraulic chamber at the time of a drive can be reduced by restricting the high pressure fluid which flows into a hydraulic chamber by the 1st orifice, and making the 2nd orifice larger than the 1st orifice.

  In the control valve according to claim 11, when the first valve member is separated from the first valve seat, the pressure of the control passage decreases, and the second valve member is seated on the second valve seat due to the pressure difference with the high pressure fluid passage. . If it does in this way, even if a 1st valve body and a 2nd valve body isolate | separate, a 2nd valve body can be seated reliably.

  In the control valve according to claim 12, the seat of the first valve member has a substantially conical surface, and the seat of the second valve member has a substantially conical surface. If it does in this way, a highly accurate sheet | seat can be manufactured by easy process.

  In the control valve according to the thirteenth aspect, the seat of the first valve member has a substantially conical surface, and the seat of the second valve member has a substantially spherical surface. If it does in this way, even if the 2nd valve member may incline, it can seat reliably.

  In the control valve according to the fourteenth aspect, the seat of the first valve member has a substantially conical surface, and the seat of the second valve member has a flat surface. If it does in this way, even if the axis | shaft of a 1st valve member and a 2nd valve member slip | deviates large, a 2nd valve member will seat reliably. Furthermore, the surface pressure when the second valve seat is seated can be reduced, and a highly reliable control valve can be obtained even in a high pressure system.

  A fifteenth aspect of the present invention is a fuel injection valve provided with the control valve having the configuration described in the ninth to thirteenth aspects. The control passage of the control valve communicates with the control chamber of the booster piston and the control chamber of the nozzle needle, and when the electric actuator is driven, the first valve member is opened and the second valve member is closed to lower the control chamber. As a result, the pressure increasing piston is driven to increase the pressure of the injected fuel and the nozzle needle is opened to perform injection. On the other hand, when the electric actuator is stopped, the first valve body is closed and the second valve body is opened to increase the pressure of the control chamber, thereby resetting the booster piston and closing the nozzle needle to stop the injection. In this way, fuel injection can be controlled.

  The fuel injection valve according to the sixteenth aspect includes an orifice in the control passage, and the timing of injection and pressure increase can be set by adjusting the orifice flow rate. By adjusting the orifice flow rate in the control passage of the booster piston, the time from the drive signal ON to the start of pressure increase can be adjusted, and by adjusting the orifice flow rate in the control passage of the nozzle needle, the time from the drive signal ON to the start of injection Can be adjusted. The injection rate waveform of the injection valve can be set by setting the pressure increase and injection timing.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a pressure-intensifying common rail injector 1 for a diesel engine using a hydraulic servo valve 3 which is a three-way control valve to which the present invention is applied. In FIG. 1, an injector 1 is connected to a common rail 2 that accumulates high-pressure fuel via a high-pressure fuel passage 21 that is a high-pressure fluid passage. A known high-pressure supply pump 23 having a discharge amount variable mechanism is connected to the common rail 2, and the fuel in the fuel tank 24 is pressurized and fed to the common rail 2.

  The injector 1 includes a pressure increasing device 4 that increases the fuel in the common rail 2 and an injection nozzle 7 that injects the fuel increased in pressure by the pressure increasing device 4. The operations of the pressure booster 4 and the injection nozzle 7 are controlled by the electromagnetic valve 5 and the hydraulic servo valve 3. The electromagnetic valve 5 is a two-position two-way valve, and opens and closes a return passage 27 serving as a low-pressure fluid passage leading to the fuel tank 24 and the hydraulic servo valve 3 to control hydraulic pressure in the servo valve control chamber 13 that is a hydraulic chamber. Increase or decrease. As the electromagnetic valve 5, a known configuration is used in which a valve body is controlled to be opened and closed by a solenoid which is an electric actuator. Details of the hydraulic servo valve 3 which is a feature of the present invention will be described later.

  The pressure booster 4 increases or decreases the pressure in the pressure increasing chamber 41 formed at the lower end of the cylinder 45 by a pressure increasing piston 44 that slides in a stepped cylinder 45 having a large and small two-stage diameter in the vertical direction in the figure. The booster piston 44 has a stepped shape with a large and small two-stage diameter. The large-diameter upper piston keeps the oil tight inside the large-diameter upper cylinder, and the small-diameter lower piston has the lower end inside the small-diameter lower cylinder. The pressure increasing chamber 41 is formed with the lower piston lower end surface and the inner wall surface of the cylinder 45 as chamber walls. A high pressure chamber 42 is formed at the upper end of the cylinder 45 with the upper piston upper end surface of the large pressure boosting piston 44 and the inner wall surface of the cylinder 45 as chamber walls, and is connected to the common rail 2 via the high pressure fuel passage 21. Yes.

  In the upper cylinder of the large diameter of the cylinder 45, the pressure increasing control chamber 11 is formed around the lower piston of the small diameter of the pressure increasing piston 44. The pressure increase control chamber 11 communicates with the hydraulic servo valve 3 through a pressure increase control passage 14 having an orifice 141, and communicates with the pressure increase chamber 41 through a flow path having a check valve 16. A spring 43 is disposed in the pressure increase control chamber 11 to urge the pressure increase piston 44 upward. At this time, the oil pressure of the high pressure chamber 42 is applied to the upper end surface of the pressure increasing piston 44, and the oil pressure of the pressure increasing control chamber 11 and the spring force of the spring 43 are applied to the lower end surface. When the pressure is reduced, the pressure-increasing piston 44 is lowered to increase the pressure of the fuel supplied to the pressure-increasing chamber 41.

  The injection nozzle 7 includes a nozzle needle 71 slidably accommodated in a nozzle body 72. The nozzle needle 71 is driven by the command piston 73 to open and close the nozzle hole 74 provided at the tip of the nozzle body 72. The fuel reservoir 75 communicates with the pressure increasing chamber 41 through the flow path 17. An injection control chamber 12 is provided above the command piston 73, and the injection control chamber 12 communicates with the hydraulic servo valve 3 through an injection control passage 15 having an orifice 151. The command piston 73 has a larger diameter than the nozzle needle 71, and a spring 76 is disposed around the connecting portion between the command piston 73 and the nozzle needle 71 to apply an upward biasing force to the command piston 73 and downward to the nozzle needle 71. Giving the urging power of. In this configuration, when the pressure in the injection control chamber 12 is lowered, the nozzle needle 71 rises together with the command piston 73 and the fuel supplied from the fuel reservoir 75 is injected.

  Next, the structure of the hydraulic servo valve 3 which is a feature of the present invention will be described with reference to FIG. As shown in the figure, the hydraulic servo valve 3 includes a cylinder 65 provided in a valve housing and an upper valve 31 as a first valve member and a lower valve 32 as a second valve member. The upper valve 31 has a substantially cylindrical shape whose upper end is closed, and the upper half portion is a sliding portion, the diameter of the lower end portion of the lower half portion having a small diameter is reduced downward to form a tapered surface (conical surface). A sheet 33 is formed. The lower valve 32 is substantially cylindrical, and the upper half is inserted and held in the cylinder of the upper valve 31, and the lower end portion is expanded downward to form a tapered sheet (conical surface) -shaped lower sheet 34. Yes. The cylinder 65 has a stepped shape with a small diameter in the middle part. The upper valve seat 63 as a first valve seat on which the upper valve 31 is seated at the upper end stepped portion and the lower valve 32 at the lower end stepped portion. Is a lower valve seat 64 as a second valve seat on which is seated. The lower valve 32 extends downward from the middle portion of the cylinder 65, and the lower end portion provided with the lower seat 34 is accommodated in the lower end portion of the large-diameter cylinder 65.

  The valve housing is formed by abutting a seat surface member 61 constituting a small diameter intermediate portion provided with valve seats 63 and 64 and a housing member 62 constituting a lower end portion of the cylinder 65. The seat surface member 61 is formed with a return port 28 as a first port that opens to the side surface of the cylinder 65 above the upper valve seat 63 and communicates with the space around the lower half of the small diameter of the upper valve 31. The other end of the return port 28 communicates with the return passage 27. The seat member 61 is further formed with a pressure increase control passage 14 and an injection control passage 15 that open to the side surface of the cylinder 65 between the valve seats 63 and 64 and communicate with the space around the middle portion of the lower valve 32. . The other ends of the pressure increase control passage 14 and the injection control passage 15 communicate with the pressure increase control chamber 11 of the pressure increase device 4 and the injection control chamber 12 of the injection nozzle 7, respectively. On the other hand, the housing member 62 is formed with a high-pressure port 22 as a second port that opens in the center of the lower end surface of the cylinder 65 and opens in a space around the lower end portion of the lower valve 31. Note that the lower end surface of the lower valve 32 facing the high pressure port 22 has a semi-cylindrical groove so that the flow of fuel flowing from the high pressure port 22 is not restricted when the lower valve 32 is opened.

  The servo valve control chamber 13 is formed at the upper end portion of the cylinder 65 on which the upper valve 31 slides with the upper end surface of the upper valve 31 and the inner wall surface of the cylinder 65 as chamber walls. The servo valve control chamber 13 communicates with the high-pressure chamber 42 of the pressure intensifier 4 through a passage having an in-orifice 25 opened on the side surface, and via the electromagnetic valve 5 in a passage having an out-orifice 26 opened on the top surface. To the return passage 27. By driving the electromagnetic valve 5, the communication between the servo valve control chamber 13 and the return passage 27 is controlled, and the upper valve 31 and the lower valve 32 move up and down integrally. Here, as shown in FIGS. 3 (a) and 3 (e), in detail, the upper end surface of the upper valve 31 is recessed at the center, and the outer peripheral edge projecting upward is in one radial direction. The groove 311 is provided. The groove 311 allows fuel to flow from the in-orifice 25 into the servo valve control chamber 13 even when the upper valve 31 is in the upper position.

  The hydraulic servo valve 3 has an area A1 of the upper end surface of the upper valve 31 larger than an area A4 of the lower end surface of the lower valve 32, and a low pressure portion communicating with the return port 28 is provided between the sliding portion and the upper seat 33. Yes. In the present embodiment, the areas of the upper sheet 33 and the lower sheet 34 are the same. However, as long as the area A4 of the lower end surface is larger than the area of the upper sheet 33, there may be a difference in sheet area. With this configuration, the seat position is switched by the pressure in the control chamber 13, and when the control chamber 13 is at a high pressure, the downward oil pressure increases and the upper seat 33 of the hydraulic servo valve 3 is closed. When the control chamber 13 becomes low pressure, the upward oil pressure increases and the lower seat 34 closes.

  The operation of the hydraulic servo valve 3 and the injector 1 will be described with reference to FIGS. As shown in FIG. 1, the electromagnetic valve (2/2 valve) 5 is configured to close in a non-energized state, and the communication between the out orifice 26 and the return passage 27 of the hydraulic servo valve 3 is blocked. . At this time, as shown in FIG. 2, the servo valve control chamber 13 is at a high pressure due to the pressure of the common rail 2 flowing from the in-orifice 25, and the upper seat 33 of the upper valve 31 is seated on the upper valve seat 63, The lower seat 34 of the lower valve 32 is separated from the lower valve seat 64. Accordingly, the pressure increase control passage 14 and the injection control passage 15 communicate with the high pressure port 22, and the pressure increase control chamber 11 and the injection control chamber 12 are also at a high pressure. For this reason, the nozzle needle 71 of the injection nozzle 7 is in the lower end position, and fuel is not injected.

When the solenoid valve 5 is energized and driven to open during injection, the out orifice 26 and the return passage 27 of the hydraulic servo valve 3 communicate with each other, and the hydraulic pressure in the servo valve control chamber 13 becomes low (the electromagnetic in FIG. 2). Valve ON stroke). Then
Upward force = (A2 + A4) × Fp> Downward force = A3 × Fp (1)
Thus, the upper and lower valves 31 and 32 move upward in the figure due to the difference between the upper and lower oil pressures. Accordingly, the upper seat 33 of the upper valve 31 is separated from the upper valve seat 63, and then the lower seat 34 of the lower valve 32 is seated on the lower valve seat 64. That is,
Upward force = A4 × Fp> Downward force = A5 × Fp (2)
Thus, the lower seat 34 of the lower valve 32 is kept closed.

  As a result, the pressure increase control passage 14 and the injection control passage 15 communicate with the return port 28, and the fuel in the pressure increase control chamber 11 and the injection control chamber 12 passes through the upper seat 33 of the hydraulic servo valve 3 and returns to the return passage 27. Spill to The nozzle needle 71 opens to open the nozzle hole 74 when the oil pressure in the injection control chamber 12 decreases and the oil pressure in the valve opening direction becomes larger than the force of the spring 76. Further, when the pressure increase control chamber 11 becomes low pressure, the pressure increase piston 44 moves downward in the drawing so as to balance the upper and lower oil pressure differences, pressurizes the fuel in the pressure increase chamber 41 and sends it to the fuel reservoir 17. Thereby, the pressurized fuel can be injected.

  Here, since the pressure increase control passage 14 leading to the pressure increase control chamber 11 and the injection control passage 15 leading to the injection control chamber 12 are provided independently, the flow rate can be controlled by the orifice 141 and the orifice 151, respectively. In the present embodiment, by causing the pressure in the injection control chamber 12 to decrease first, the valve opening of the nozzle needle 71 becomes faster and the injection responsiveness is improved. In this case, the fuel to be injected has a common rail pressure at the start of injection, but the pressure increasing piston 44 pressurizes the fuel in the pressure increasing chamber 41, resulting in an extremely high pressure during the injection. Therefore, a delta-shaped injection rate waveform with a low initial stage and a high late stage can be formed, which is advantageous for achieving both reduction of emission and high output.

At the end of injection, the energization of the electromagnetic valve 5 is stopped, and the communication between the out orifice 26 of the hydraulic servo valve 3 and the return passage 27 is shut off. As a result, the hydraulic pressure in the servo valve control chamber 13 rises again to a high pressure (the electromagnetic valve OFF process in FIG. 2). Then
Upward force = A4 × Fp <Downward force = (A1 + A5) × Fp (3)
Thus, the upper and lower valves 31 and 32 move downward in the figure due to the hydraulic pressure difference between the upper and lower sides. Accordingly, the lower seat 34 of the lower valve 32 is separated from the lower valve seat 64, and then the upper seat 33 of the upper valve 31 is seated on the upper valve seat 6,
Upward force = (A2 + A4) × Fp <Downward force = (A1 + A3) × Fp (4)
Thus, the upper seat 33 of the upper valve 31 is kept closed.

  As a result, the pressure increase control passage 14 and the injection control passage 15 and the high pressure port 22 communicate with each other, and fuel of the common rail pressure flows into the pressure increase control chamber 11 and the injection control chamber 12 through the lower seat 34 of the hydraulic servo valve 3. The pressure becomes high again. Then, the nozzle needle 71 of the injection nozzle 7 is lowered to close the injection hole, and the pressure increasing piston 44 of the pressure increasing device 4 is returned to the initial position.

  Here, as described above, the flow rate of the pressure increase control passage 14 and the injection control passage 15 can be independently controlled by the orifice 141 and the orifice 151, and in this embodiment, the pressure in the injection control chamber 12 rises first. Configured to do. Accordingly, first, the injection control chamber 12 becomes high pressure, and the nozzle needle 71 closes at a high speed due to the area difference between the command piston 73 and the nozzle needle 71, so that sharp cutting is possible. Next, the pressure-increasing control chamber 11 becomes high pressure, and the pressure-increasing piston 44 is moved in the return direction (upward in the figure) by the spring 43. At this time, the pressure increasing chamber 41 maintains the common rail pressure by the flow of fuel from the check valve 16.

  As described above, according to the present invention, it is possible to provide the hydraulic servo valve 6 that can reduce the drive energy of the electromagnetic valve 5 and can always reduce the leak without requiring high processing accuracy and positioning accuracy. Further, by constituting the plurality of valve members of the hydraulic servo valve 6, that is, the upper valve 31 having the upper seat 33 and the lower valve 32 having the lower seat 34, the seat member 61 having the valve seats 63, 64 can be used. Thus, the valves 31 and 32 can be inserted from both sides, and can be easily assembled. As shown in FIG. 3A, the lower valve 32 is roughly guided by the center hole of the upper valve 31, and is adjusted so that a specified lift amount can be secured in a state where the tip tapered portion is in contact. Accordingly, when the upper seat 33 is closed, the upper valve 31 pushes down the lower valve 32 to open the lower seat 34, and when the lower seat 34 is closed, the lower valve 32 pushes up the upper valve 31 to open the upper seat 33. The lower valve 32 is separated from the upper valve 31 after the valve is opened, so that the energy at the time of sitting of the upper valve 31 can be dispersed to prevent bounce.

  3 (b) to 3 (d) show another embodiment of the hydraulic servo valve 6. FIG. FIG. 3B is a second embodiment of the present invention, and the diameter of the seat surface of the upper valve seat 63 on which the upper seat 33 of the upper valve 31 is seated is reduced downward, like the upper seat 33 facing the lower seat. The seat surface of the lower valve seat 64 on which the lower seat 34 of the lower valve 32 is seated is a tapered surface that expands in the downward direction, like the opposing lower seat 34. Thus, if a seat seat surface is made into a taper shape, a reliable sheet | seat can be manufactured by easy process.

  FIG. 3C shows a third embodiment of the present invention. The upper and lower valve seats 63 and 64 have the same tapered surface as that of the second embodiment, and the lower seat 34 of the lower valve 32 is formed in a spherical shape. In this case, since the seat can be formed even if the axis of the lower valve 32 is inclined, the reliability is further improved.

  FIG. 3D shows a fourth embodiment of the present invention, in which the lower seat 34 of the lower valve 32 is configured to be flat (planar). In this way, when the upper valve 31 and the lower valve 32 are misaligned, the upper valve 31 can be reliably sealed even if the clearance between the cylinder inner peripheral surface of the upper valve 31 and the outer peripheral surface of the lower valve 32 is small. Furthermore, the surface pressure when the lower seat 34 is seated can be reduced, and a highly reliable control valve can be obtained even in a high pressure system. In the present embodiment, a through hole 35 that penetrates the upper valve 31 and the lower valve 32 is formed, and an in-orifice 25 is provided at the upper end thereof. As a result, the servo valve control chamber 13 communicates with the common rail 2 via the high-pressure port 22, so that the passage configuration becomes simpler.

  4A to 4C show still another embodiment of the hydraulic servo valve 6. In the above embodiment, the lower valve is inserted and held in the upper valve 31. However, as shown in the drawing, a shaft for guiding the lower valve 32 is provided on the upper valve 31, and the lower valve 32 is a spring as a biasing member. It is good also as a structure which moves integrally by urging | biasing by 37. FIG. 4A shows a fifth embodiment of the present invention. In the upper valve 31, a narrow diameter portion extending below the upper seat 33 is a guide shaft 36, and the lower end thereof is the lower end of the cylinder 65. Located in the large diameter part. The lower valve 32 is hemispherical, the upper seat 34 is spherical, and has a recess 38 in which the guide shaft 36 is fitted at the center of the upper surface. The lower valve 32 is pressed so as not to be separated from the upper valve 31 by a spring 37 disposed on the lower surface side thereof.

  FIG. 4B shows a sixth embodiment of the present invention. In the basic configuration of the fifth embodiment, the lower seat 34 of the lower valve 32 has a tapered surface instead of a spherical surface. FIG. 4C shows a seventh embodiment of the present invention. In the basic configuration of the fifth embodiment, instead of the lower valve 32 having a T-shaped cross section and the lower seat 34 having a spherical shape, FIG. It is flat. The spring 37 is disposed around the lower half portion of the lower diameter of the lower valve 32. In this configuration, since the seat can be formed even if the shafts of the upper valve 31 and the lower valve 32 are misaligned, the concave portion 38 is not provided in the lower valve 32.

  As described above, according to the present invention, it is possible to realize a control valve capable of highly accurate pressure increase control and injection control with a simple configuration. Note that the present invention can also be applied as a control valve driven by a small solenoid in a conventional booster injector having two actuators. Moreover, it is applicable also as fluid control valves other than a fuel injection valve.

It is a figure which shows the whole structure of the pressure | voltage increase type common rail injector for diesel engines to which the control valve of this invention is applied. It is a figure for demonstrating the structure and action | operation of the hydraulic servo valve in the 1st Embodiment of this invention. (A)-(d) is a detailed block diagram of the hydraulic servo valve in the 1st-4th embodiment of this invention, respectively. (A)-(c) is a detailed block diagram of the hydraulic servo valve in the 5th-7th embodiment of this invention, respectively. It is a figure which shows the whole structure of the conventional pressure increase type common rail injector.

Explanation of symbols

1 Injector 11 Pressure increase control room (control room)
12 Injection control room (control room)
13 Servo valve control room (hydraulic room)
14 Pressure increase control passage (control passage)
15 Injection control passage (control passage)
2 Common rail 21 High pressure fuel passage (High pressure fluid passage)
22 High pressure port (second port)
23 Fuel pump 24 Fuel tank 25 In-orifice (first orifice)
26 Out orifice (second orifice)
27 Return passage (low pressure fluid passage)
28 Return port (1st port)
3 Hydraulic servo valve (control valve)
31 Upper valve (first valve member)
32 Lower valve (second valve member)
33 Upper seat (first valve member)
34 Lower seat (second valve member)
4 Pressure increase control valve 41 Pressure increase chamber 42 High pressure chamber 43 Spring 44 Pressure increase piston 5 Electromagnetic valve 61 Seat member (valve housing)
62 Housing member (valve housing)
63 Upper valve seat (first valve seat)
64 Lower valve seat (second valve seat)
65 cylinders 7 injection nozzles 71 nozzle needles

Claims (16)

  When the second valve member is inserted and disposed inside the first valve member housed in the valve housing, and the first valve member is seated on the first valve seat, the second valve member is separated from the second valve seat. When the second port communicates with the control passage and the second valve member is seated on the second valve seat, the first valve member is separated from the first valve seat, and the first port and the control passage are A control valve configured to selectively communicate the control passage and the first port or the second port by communicating with each other.   When the first valve member and the second valve member are closely arranged in the valve housing using a biasing member and the first valve member is seated on the first valve seat, the second valve member is separated from the second valve seat. When the second port and the control passage communicate with each other and the second valve member is seated on the second valve seat, the first valve member is separated from the first valve seat and A control valve configured to selectively communicate the control passage and the first port or the second port by communicating the control passage.   The control passage is disposed between the first valve seat and the second valve seat, the first port is disposed on the opposite side of the control passage with respect to the first valve seat, and the second valve seat is disposed on the second valve seat. The control valve according to claim 1, wherein the second port is disposed on the opposite side of the control passage.   The first valve member slides in a cylinder provided in the valve housing, and the seat diameter of the first valve member and the seat diameter of the second valve member are set with respect to the sliding diameter of the first valve member. 4. The control valve according to claim 1, wherein the control valve is reduced.   The control valve according to claim 4, wherein the second valve member has no sliding portion with respect to the valve housing and the first valve member.   The control valve according to claim 4 or 5, wherein the first valve seat and the second valve seat are arranged at different positions in the axial direction on an inner periphery of a cylinder provided in the valve housing.   The first port communicates with the low pressure fluid passage, the second port communicates with the high pressure fluid passage, and the seat diameter of the first valve member and the seat diameter of the second valve member are equal. Or control valve as described.   The first port communicates with a low pressure fluid passage, the second port communicates with a high pressure fluid passage, and the seat diameter of the first valve member is smaller than the seat diameter of the second valve member. Control valve.   A hydraulic chamber surrounded by an end surface of the sliding portion of the first valve member and a cylinder inner wall surface provided in the valve housing is provided, and the pressure of the hydraulic chamber is controlled by an electric actuator to drive the first valve member. The control valve according to any one of claims 1 to 8.   10. The passage according to claim 9, wherein the hydraulic chamber includes a passage communicating with the high pressure fluid passage through the first orifice, and a passage communicating with the low pressure fluid passage through the valve body controlled by the second orifice and the electric actuator. Control valve.   The pressure of the control passage decreases when the first valve member is separated from the first valve seat, and the second valve member is seated on the second valve seat due to a pressure difference with the high pressure fluid passage. 10. The control valve according to 10.   The control valve according to any one of claims 1 to 11, wherein the seat of the first valve member has a substantially conical surface, and the seat of the second valve member has a substantially conical surface.   The control valve according to any one of claims 1 to 11, wherein the seat of the first valve member has a substantially conical surface, and the seat of the second valve member has a substantially spherical surface.   The control valve according to claim 1, wherein the seat of the first valve member has a substantially conical surface, and the seat of the second valve member has a flat surface.   14. A fuel injection valve comprising the control valve according to any one of claims 9 to 13, wherein the control passage of the control valve communicates with a control chamber of a booster piston and a control chamber of a nozzle needle. When the actuator is driven, the first valve member is opened and the second valve member is closed to lower the control chamber, thereby driving the pressure-increasing piston to increase the injected fuel and the nozzle needle. When the electric actuator is stopped, the first valve member is closed and the second valve member is opened to open the control chamber to a high pressure, thereby resetting the pressure increasing piston. A fuel injection valve characterized in that the nozzle needle is closed to stop the injection. The fuel injection valve according to claim 15, wherein an orifice is provided in the control passage, and the timing of injection and pressure increase can be set by adjusting the flow rate of the orifice.

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