JP2012172648A - Injector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress displacement in a radial direction of a mover 32, to suppress variation of attraction by a stator 33, and to stabilize the reduction speed of a back pressure, in a solenoid valve 3 of an injector.SOLUTION: The solenoid valve 3 has a spherical body 56 for transmitting force between a coil spring 34 and a mover 32, the spherical body 56 is received by a receiving surface 57 provided on the mover 32 and supported freely slidably in an axial direction by a stator 33, and the receiving surface 57 is provided so as to form a recess to be continuously reduced in diameter toward an energizing direction (distal end side) by the coil spring 34. Thus, by being abutted to the mover 32 through the receiving surface 57, the spherical body 56 exerts abutting force to the mover 32 so as to dissolve the displacement in the radial direction. Thus, in the solenoid valve 3, the displacement in the radial direction of the mover 32 is suppressed, the variation of the attraction by the stator 33 is suppressed, and the reduction speed of the back pressure is stabilized.

Description

  The present invention relates to an injector for injecting and supplying fuel to an internal combustion engine.

Conventionally, it is known that an injector 100 that injects and supplies fuel with an ultrahigh injection pressure exceeding 100 MPa has a structure as shown in FIG.
That is, the injector 100 includes a nozzle needle 102 that opens and closes the nozzle hole 101, and forms a back pressure chamber 103 for exerting fuel pressure in a direction (valve closing direction) for closing the nozzle hole 101 with respect to the nozzle needle 102, The nozzle hole 102 is closed or opened by changing the fuel inflow / outflow state in the back pressure chamber 103 and increasing / decreasing the fuel pressure in the back pressure chamber 103 (hereinafter referred to as back pressure).

  The injector 100 includes an electromagnetic valve 105 that opens and closes the fuel outlet 104 of the back pressure chamber 103. The back pressure increases when the outlet 104 is closed by the electromagnetic valve 105 and decreases when the outlet 104 is opened. . Here, the electromagnetic valve 105 includes a mover 107 and a stator 108 that are excited by energization of the solenoid coil 106, a coil spring 109 that biases the mover 107 in a direction opposite to the direction of attraction by the stator 108, and The valve body 110 that opens and closes the outlet 104 is provided.

  The solenoid valve 105 sucks the movable element 107 toward the stator 108 in response to the start of energization of the solenoid coil 106, thereby opening the outlet 104 by the valve body 110 and the coil spring 109 by the movable element 107. And the movable element 107 is biased by the coil spring 109 in response to the stop of energization of the solenoid coil 106, thereby pulling the movable element 107 away from the stator 108 and closing the outlet 104 by the valve body 110.

  By the way, according to the injector 100, the movable element 107 is provided with the sliding shaft portion 112 integrated with the plate-like magnetic portion 111 made of a magnetic material, and the sliding shaft portion 112 is axially formed by the valve body 113. It is slidably supported. Further, the valve body 110 is held at the tip of the sliding shaft portion 112. And by employ | adopting such a structure, in the injector 100, the movement to the axial direction of the valve body 110 is stabilized, the speed | rate of increase / decrease in a back pressure is stabilized, and the fluctuation | variation of an injection characteristic is suppressed.

In recent years, inferior fuel with a lot of foreign matters has been circulated, and even when such inferior fuel is used, a structure capable of maintaining the reliability for injection control is required in the injector 100.
That is, when bad fuel with a large amount of foreign matter is introduced into the injector 100 and injected, foreign matter accumulates in a very small sliding gap between the sliding shaft portion 112 and the valve body 113, and the sliding shaft portion 112. There is a risk that a sliding failure will occur, and when such a sliding failure occurs, the jetting characteristics fluctuate greatly.

In view of this, an injector in which the sliding shaft portion is omitted and the movable element is provided in a plate shape is known (for example, see Patent Document 1).
However, according to this injector, the mover may be displaced in the radial direction during movement when opening and closing the outlet of the back pressure chamber. And in particular, when the mover is displaced in the radial direction when moving to the rear end side to open the outlet, the suction force by the stator fluctuates and the movement of the valve body becomes unstable, The reduction rate of the back pressure becomes unstable, and the injection characteristics fluctuate.

JP 2003-193939 A

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to provide a displacement of the mover in the radial direction when the slider is not provided with a sliding shaft portion in the solenoid valve of the injector. This is to suppress the fluctuation of the suction force by the stator and stabilize the decrease rate of the back pressure.

[Means of Claim 1]
According to the means of claim 1, the injector includes a nozzle needle that opens and closes the nozzle hole, forms a back pressure chamber for applying fuel pressure to the nozzle needle in a direction to close the nozzle hole, The nozzle hole is closed or opened by changing the fuel inflow / outflow state and increasing / decreasing the fuel pressure (back pressure) in the back pressure chamber. The injector includes an electromagnetic valve that opens and closes the fuel outlet of the back pressure chamber. The back pressure increases when the outlet is closed by the electromagnetic valve and decreases when the outlet is opened.

  The electromagnetic valve includes a movable element and a stator that are excited by energizing the solenoid coil and exert an attractive force in the axial direction, a spring that biases the movable element in a direction opposite to the attractive direction by the fixed element, a spring, A solenoid coil having a spherical body that is interposed between the movable element and transmits a force between the spring and the movable element, and a plate-shaped valve element that is fitted to the distal end of the movable element to open and close the outlet. By attracting the mover toward the stator in response to the start of energization to the stator, the outlet is opened and the spring is compressed via the sphere by the mover. By energizing the mover via the, the mover is separated from the stator and the outlet is closed.

Further, the sphere is supported so as to be slidable in the axial direction, and is received by a receiving surface provided on the mover, and the receiving surface forms a recess whose diameter is continuously reduced in the biasing direction by the spring. It is provided to do.
Thereby, the spherical body can exert an abutting force on the movable element so as to eliminate the positional deviation in the radial direction by contacting the movable element via the receiving surface.

For this reason, in the solenoid valve of the injector, when the mover is not provided with a sliding shaft, the displacement of the mover in the radial direction is suppressed, the fluctuation of the suction force by the stator is suppressed, and the reduction rate of the back pressure is increased. It can be stabilized.
Furthermore, since the valve body that opens and closes the outlet is provided in a plate shape and is fitted into the tip of the mover, the amount of movement of the valve body when the outlet is opened can be adjusted by adjusting the thickness of the valve body. Can be varied.

[Means of claim 2]
According to the means of claim 2, the valve body is a non-magnetic body.
Thereby, delivery of the magnetic flux between a valve body and a stator can be suppressed, and the fall of the attractive force which acts on a needle | mover can be prevented.

[Means of claim 3]
According to the third aspect of the present invention, the electromagnetic valve has a stopper mechanism that prevents the magnetic part of the mover and the magnetic part of the stator from contacting each other, and the stopper mechanism is fixed to each of the mover and the stator. It is comprised by the contact part made. Then, the contact portion of the mover and the contact portion of the stator are provided so that at least one protrudes toward the other, and by contact of the contact portion of the mover and the contact portion of the stator, Contact between the magnetic part of the mover and the magnetic part of the stator is prevented.

  A soft magnetic material having a low hardness such as electromagnetic stainless steel, silicon steel, or low carbon steel is used as the material of the magnetic part of each of the mover and the stator from the viewpoint of magnetic characteristics. For this reason, if the magnetic part of a needle | mover and the magnetic part of a stator are made to contact | abut directly, progress of wear will become quick. Therefore, by separately fixing the contact portion to each of the mover and the stator, the material of the contact portion is made of high hardness alloy steel, stainless steel, etc., so that the magnetic portion of each of the mover and the stator is The progress of wear can be suppressed.

[Means of claim 4]
According to the fourth aspect of the present invention, the mover is provided in a plate shape, and when the outflow port is opened, the moment due to the dynamic pressure of the fuel flowing out from the back pressure chamber, the moment due to the suction force of the stator, and the biasing force of the spring The moment and the moment due to the weight of the mover act on the mover. And the attraction force of the stator, the biasing force of the spring, and the dead weight of the mover are due to all moments acting on the mover when the outlet is opened, even when the back pressure is the lowest pressure during actual use. Is set to point in a direction perpendicular to the axial direction.

  Thereby, when the mover is moving to open the outlet, the tilt can be corrected autonomously so as to be directed in a direction perpendicular to the axial direction. For this reason, since the fluctuation | variation of a suction force can further be suppressed, the decreasing speed of a back pressure can be stabilized further.

[Means of claim 5]
According to the means of claim 5, the outflow port opens in a plane perpendicular to the axial direction, and the valve body has a closing surface that comes into surface contact with the plane and closes the outflow port.
Thereby, an outflow port is closed by the face sheet | seat which utilizes the overlap of surfaces. For this reason, the structure which closes an outflow port can be provided easily compared with the structure which closes an outflow port by the wire sheet with respect to a taper surface, for example.

It is a whole block diagram of an injector (Example). (A) is a principal part block diagram of an injector, (b) is a top view which shows the outflow port of a back pressure chamber (Example). It is explanatory drawing which shows the various force which acts on a needle | mover at the time of open | release of a back pressure chamber while showing the maximum inclination state of a needle | mover (Example). (A) is a whole block diagram of an injector, (b) is a principal part block diagram of an injector (conventional example).

  The injector of the embodiment includes a nozzle needle that opens and closes a nozzle hole, forms a back pressure chamber for exerting fuel pressure in the direction of closing the nozzle hole with respect to the nozzle needle, and determines the flow of fuel in and out of the back pressure chamber. By changing the fuel pressure (back pressure) in the back pressure chamber in a variable manner, the nozzle hole is closed or opened by the nozzle needle. The injector includes an electromagnetic valve that opens and closes the fuel outlet of the back pressure chamber. The back pressure increases when the outlet is closed by the electromagnetic valve and decreases when the outlet is opened.

  The electromagnetic valve includes a movable element and a stator that are excited by energizing the solenoid coil and exert an attractive force in the axial direction, a spring that biases the movable element in a direction opposite to the attractive direction by the fixed element, a spring, A solenoid coil having a spherical body that is interposed between the movable element and transmits a force between the spring and the movable element, and a plate-shaped valve element that is fitted to the distal end of the movable element to open and close the outlet. By attracting the mover toward the stator in response to the start of energization to the stator, the outlet is opened and the spring is compressed via the sphere by the mover. By energizing the mover via the, the mover is separated from the stator and the outlet is closed.

  Further, the sphere is supported so as to be slidable in the axial direction, and is received by a receiving surface provided on the mover, and the receiving surface forms a recess whose diameter is continuously reduced in the biasing direction by the spring. It is provided to do.

The valve body is a nonmagnetic material.
The solenoid valve also has a stopper mechanism that prevents the magnetic part of the mover and the magnetic part of the stator from contacting each other, and the stopper mechanism is configured by a contact part fixed to each of the mover and the stator. Is done. Then, the contact portion of the mover and the contact portion of the stator are provided so that at least one protrudes toward the other, and by contact of the contact portion of the mover and the contact portion of the stator, Contact between the magnetic part of the mover and the magnetic part of the stator is prevented.

The mover is provided in a plate shape. When the outlet is opened, the moment due to the dynamic pressure of the fuel flowing out from the back pressure chamber, the moment due to the attracting force of the stator, the moment due to the spring biasing force, and the weight of the mover The moment due to acts on the mover. And the attraction force of the stator, the biasing force of the spring, and the dead weight of the mover are due to all moments acting on the mover when the outlet is opened, even when the back pressure is the lowest pressure during actual use. Is set to point in a direction perpendicular to the axial direction.
Furthermore, the outflow port opens in a plane perpendicular to the axial direction, and the valve body has a closing surface that is in surface contact with the plane and closes the outflow port.

[Configuration of Example]
The structure of the injector 1 of an Example is demonstrated using FIG. 1 and FIG.
The injector 1 is capable of injecting and supplying fuel with an ultrahigh injection pressure exceeding 100 MPa. For example, the injector 1 is mounted on a diesel engine (not shown) and directly supplies fuel to a combustion chamber (not shown). Supply to the jet.

  The injector 1 includes an injection nozzle 2 for injecting high-pressure fuel, and an electromagnetic valve 3 as an actuator for guiding the high-pressure fuel received from the fuel supply source toward the injection nozzle 2 and opening the injection nozzle 2. A main body 4 and a connector 5 for energizing the electromagnetic valve 3 are provided. The injection nozzle 2 is fastened to the front end in the axial direction of the main body 4 via the tip packing 6 and the connector is connected to the rear end in the axial direction of the main body 4. It is comprised by fastening 5.

  The injection nozzle 2 has a nozzle needle 9 that moves in the axial direction to open and close the nozzle hole 8, a nozzle body 10 that supports and accommodates the nozzle needle 9 slidably in the axial direction, and a direction in which the nozzle hole 8 is closed. A coil spring 11 for urging the nozzle needle 9 (hereinafter referred to as a valve closing direction), and a tubular member 13 for forming a back pressure chamber 12 for applying fuel pressure to the nozzle needle 9 in the valve closing direction; Have The nozzle body 10 has a cylinder 14 which is provided in a substantially cylindrical shape and opens at the rear end in the axial direction, and the nozzle needle 9 is slidably supported by the cylinder 14 and accommodated therein.

The cylinder 14 communicates with the high pressure flow path 15 provided in the main body 4 and the chip packing 6 by fastening the injection nozzle 2 and the main body 4 via the chip packing 6. High pressure fuel is led from 15.
Note that the high-pressure channel 15 is a channel through which high-pressure fuel received from a fuel supply source flows without passing through various clearances and the like and without being reduced in pressure.

  The nozzle needle 9 forms a sliding shaft portion 17 whose central portion is slidably supported by the nozzle body 10. A nozzle chamber 18 for applying fuel pressure in a direction (hereinafter referred to as a valve opening direction) for opening the nozzle hole 8 with respect to the nozzle needle 9 is formed by a portion on the tip side of the sliding shaft portion 17. . A spring chamber 19 that accommodates the coil spring 11 is formed by a portion on the rear end side of the sliding shaft portion 17, and high-pressure fuel flows from the high-pressure flow path 15 into the spring chamber 19. The sliding shaft portion 17 is chamfered at a part of its outer peripheral surface in order to ensure communication between the nozzle chamber 18 and the spring chamber 19 and guide high-pressure fuel to the nozzle chamber 18.

  In addition, a seat surface 21 on which the seat portion 20 provided at the tip of the nozzle needle 9 is attached and detached is provided at the tip of the cylinder 14, and the nozzle hole 8 is further on the tip of the cylinder 14 on the tip side. It is open. For this reason, when the seat portion 20 is detached from the seat surface 21, the nozzle hole 18 and the nozzle chamber 18 are opened and closed, and fuel injection through the nozzle hole 8 is started or stopped.

Further, the rearmost end portion of the nozzle needle 9 forms a second sliding shaft portion 22 that is slidably supported in the axial direction by the cylindrical member 13.
Here, the coil spring 11 is set so as to be expandable and contractable in the axial direction by the shim 23 and the tubular member 13 disposed at the rear end of the sliding shaft portion 17, and is accommodated in the spring chamber 19. Thus, the coil spring 11 urges the nozzle needle 9 toward the axial front end side (valve closing direction), and urges the cylindrical member 13 toward the axial rear end side to press-contact the tip packing 6. .

  For this reason, the inner peripheral region of the cylindrical member 13 is sealed at the front end side by the second sliding shaft portion 22 and at the rear end side by the chip packing 6. The high-pressure fuel flows into and out of the sealed inner peripheral region, thereby providing a function as the back pressure chamber 12.

  That is, the tip packing 6 is provided with an inflow path 25 for allowing high-pressure fuel to flow into the back pressure chamber 12 and an outflow path 26 for allowing fuel to flow out from the back pressure chamber 12. Restrictions 27 and 28 are provided in each of the paths 26. The injection nozzle 2 and the tip packing 6 are fastened so that both the inflow path 25 and the outflow path 26 are connected to the back pressure chamber 12.

The inflow path 25 is provided so as to branch from the high pressure flow path 15 in the chip packing 6, and the outflow path 26 is opened and closed between the low pressure flow path (not shown) of the main body 4 by the electromagnetic valve 3. It is provided to be.
Here, the low-pressure channel is a fuel channel through which a fuel whose pressure is significantly lower than the fuel pressure in the high-pressure channel 15 flows, and the high-pressure fuel flows in a state where the pressure is reduced by passing through various clearances and the like. This is a flow path.

For this reason, the fuel pressure (back pressure) in the back pressure chamber 12 is increased or decreased by varying the flow state of the fuel into the back pressure chamber 12 through the inflow passage 25 and the outflow passage 26 according to the operation of the electromagnetic valve 3. The nozzle needle 9 can be operated to drive in the valve closing direction or the valve opening direction.
The throttles 27 and 28 are provided so that the back pressure is reliably reduced by the communication between the outflow passage 26 and the low-pressure passage by opening the solenoid valve 3. The throttle 28 is provided at the downstream end of the outflow passage 26 and opens at the rear end face of the tip packing 6. The opening at the rear end face of the tip packing 6 of the throttle 28 has a flow of fuel in the back pressure chamber 12. Make exit 29.

  The electromagnetic valve 3 is energized by energizing the solenoid coil 31 and biases the mover 32 and the stator 33 that exert an attractive force in the axial direction, and the mover 32 in a direction opposite to the attracting direction by the stator 33. A coil spring 34 is provided. Then, the solenoid valve 3 attracts the mover 32 toward the stator 33 in response to the start of energization of the solenoid coil 31, thereby opening the outlet 29 to the low-pressure flow path and to the solenoid coil 31. By energizing the mover 32 by the coil spring 34 in response to the energization stop, the mover 32 is separated from the stator 33 and the outlet 29 is closed with respect to the low-pressure flow path.

  With the above configuration, according to the injector 1, when the outlet 29 is opened to the low pressure flow path in response to the start of energization of the solenoid coil 31, the back pressure is reduced and the nozzle needle 9 is axially moved. Since the resultant resultant force increases in the valve opening direction, the nozzle needle 9 is driven in the valve opening direction to open the space between the nozzle hole 8 and the nozzle chamber 18, and fuel injection starts.

  Further, when the outlet 29 is closed with respect to the low pressure flow path in response to the stop of energization of the solenoid coil 31, the back pressure rises and the resultant force acting in the axial direction on the nozzle needle 9 is greatly increased in the valve closing direction. Therefore, the nozzle needle 9 is driven in the valve closing direction to close the space between the nozzle hole 8 and the nozzle chamber 18, and fuel injection stops.

[Features of Examples]
The characteristic of the injector 1 of an Example is demonstrated using FIGS. 1-3.
First, the movable element 32 is provided in a plate shape, and a portion excluding the central part 36 including the axis of the injector 1 forms a movable element side magnetic part 37 through which the magnetic flux passes in the movable element 32.
In addition, the stator 33 passes the magnetic flux on the inner peripheral side of the solenoid coil 31 and forms an inner core 39 that forms a cylindrical space that houses the coil spring 34, and the outer core 40 passes the magnetic flux on the outer peripheral side of the solenoid coil 31. And have.

  Then, on the distal end side of the solenoid coil 31, the inner core 39 and the outer core 40 are arranged with the nonmagnetic portion 41 sandwiched in the radial direction. Further, the inner core 39 has a stator side magnetic part 42 through which the magnetic flux passes in the stator 33 except for the inner peripheral part on the front end side, and the outer core 40 forms the stator side magnetic part 42 as a whole.

  With such a configuration of the mover 32 and the stator 33, the magnetic flux is between the stator side magnetic part 42 of the inner core 39 and the stator side magnetic part 42 of the outer core 40 on the tip side of the solenoid coil 31. Since it is delivered via the mover side magnetic part 37 without being delivered directly, the stator 33 can reliably attract the mover 32.

  Moreover, the center part 36 of the needle | mover 32 and the inner peripheral part at the front end side of the inner core 39 are made of a material having a hardness higher than that of the needle-side and stator-side magnetic parts 37 and 42. A stopper mechanism 43 that prevents contact between the side magnetic part 37 and the stator side magnetic part 42 is configured. That is, the center portion 36 of the mover 32 and the inner peripheral portion on the front end side of the inner core 39 are respectively contacted with each other by the movement toward the rear end side of the mover 32 due to excitation. The mover side and the stator side contact portions 44 and 45 are fixed to the mover 32 and the stator 33, respectively, and constitute a stopper mechanism 43.

  The mover side contact portion 44 is provided so as to protrude toward the rear end side of the mover side magnetic portion 37 toward the stator side contact portion 45, and the stator side contact portion 45 The inner and outer cores 39 and 40 are provided so as to be flush with the stator side magnetic portion 42. For this reason, the contact between the mover side magnetic part 37 and the stator side magnetic part 42 can be reliably prevented by the contact of the mover side and stator side contact parts 44 and 45 in the stopper mechanism 43. .

Next, according to the electromagnetic valve 3 of the injector 1, a hole 48 a into which the plate-like valve body 48 is fitted is provided on the distal end side of the central portion 36 of the mover 32. The body 48 opens and closes.
Here, the hole 48 a opens toward the distal end side, and the valve body 48 is fitted in the hole 48 a so that the distal end surface protrudes further toward the distal end side than the distal end of the movable element 32.

In addition, the outlet port 29 opens in a circular opening surface 49 provided on the rear end surface of the tip packing 6, and the valve body 48 allows the outlet surface 29 to be in contact with the opening surface 49. Close. That is, the front end surface of the valve body 48 forms a closing surface 50 that closes the outflow port 29, and the outflow port 29 is closed when the closing surface 50 comes into surface contact with the opening surface 49.
In addition, the valve body 48 is a non-magnetic material, and is provided with a material (for example, ceramic) whose hardness is higher than that of the mover side and stator side magnetic portions 37 and 42.

  An annular recess 52 is provided around the opening surface 49 on the rear end face of the chip packing 6. A plurality of grooves 53 extend radially outward from the recess 52, and the grooves 53 are connected to an annular groove 54 provided on the outer periphery side of the recess 52. Further, the chip packing 6 is fastened to the main body 4 so that the groove 54 communicates with the low-pressure channel of the main body 4. For this reason, when the outlet port 29 is opened, the fuel in the back pressure chamber 12 is released to the low pressure flow path through the grooves 53 and 54.

  Next, according to the electromagnetic valve 3 of the injector 1, the sphere 56 is interposed between the coil spring 34 and the mover 32, and the sphere 56 transmits a force between the coil spring 34 and the mover 32.

  The spherical body 56 is received by a receiving surface 57 provided at the rear end portion of the central portion 36 that forms the mover side contact portion 44, and is axially formed by the front end side inner peripheral portion that forms the stator side contact portion 45. The coil spring 34 is slidably supported and is urged toward the tip side. In addition, the receiving surface 57 is provided so as to form a conical taper-shaped depression continuously reducing in diameter toward the tip end side, and the movable element side contact portion 44 is formed in an annular shape on the outer peripheral side of the receiving surface 57. Abuts on the stator side abutting portion 45.

  When energization of the solenoid coil 31 is started, the mover 32 is attracted toward the stator 33 and moved to the rear end side, and the outlet port 29 is opened by the valve body 48 and the ball 56 is interposed. The coil spring 34 is compressed. When energization of the solenoid coil 31 is stopped, the mover 32 is urged toward the distal end side by the coil spring 34 via the spherical body 56 and moves toward the distal end side, and is separated from the stator 33 to be separated from the valve body 48. To close the outlet 29.

Further, when the outlet 29 is opened, the following moment acts on the mover 32.
That is, the moment due to the dynamic pressure of the fuel flowing out from the back pressure chamber 12, the moment due to the attracting force of the stator 33, the moment due to the biasing force of the coil spring 34, and the moment due to the dead weight of the mover 32 are movable when the outlet 29 is opened. It acts on the child 32. Since the movable element 32 is not supported in the axial direction, there is a possibility that the movable element 32 is inclined from an ideal inclined state (that is, a state perpendicular to the axial direction) due to the action of these moments.

For this reason, the movable element 32 is provided so as to avoid contact with the stator 33 other than the stopper mechanism 43 even when inclined.
Further, the maximum inclination state in which the movable element 32 is most inclined from the ideal state while avoiding contact with the stator 33 other than the stopper mechanism 43 is a state as shown in FIG. That is, in the maximum inclination state, the movable element side contact portion 44 contacts the stator side contact portion 45 at one point to form a stopper side contact point 59 and the valve body 48 contacts the chip packing 6 at one point. The valve portion side contact point 60 is formed, and the stopper side and valve portion side contact points 59 and 60 are formed across the axis of the mover 32.

  In the electromagnetic valve 3, the stator 33 is arranged so that the movable element 32 autonomously corrects the inclination and directs an ideal inclination state by various moments acting on the movable element 32 when the outlet port 29 is opened. The attraction force, the urging force of the coil spring 34, and the weight of the mover 32 are set.

That is, even when the mover 32 is in the maximum inclined state and the back pressure is the lowest pressure in actual use, the mover 32 is ideal due to all moments acting on the mover 32 when the outlet 29 is opened. The attracting force of the stator 33, the urging force of the coil spring 34, and the weight of the movable element 32 are set so as to direct the inclined state.
In addition, the rotation center by various moments which act on the needle | mover 32 when the outflow port 29 is open | released is the stopper side contact point 59, for example.

[Effects of Examples]
According to the injector 1 of the embodiment, the electromagnetic valve 3 includes the sphere 56 that is interposed between the coil spring 34 and the movable element 32 and transmits a force between the coil spring 34 and the movable element 32. 56 is received by a receiving surface 57 provided on the mover 32 and is supported by the stator 33 so as to be slidable in the axial direction. The receiving surface 57 is directed toward the urging direction (front end side) by the coil spring 34. It is provided so as to form a recess having a continuously reduced diameter.

  Thereby, the spherical body 56 can exert a contact force on the movable element 32 so as to eliminate the positional deviation in the radial direction by contacting the movable element 32 via the receiving surface 57. For this reason, in the solenoid valve 3 of the injector 1, when the movable shaft 32 is not provided with the sliding shaft portion, the displacement of the movable member 32 in the radial direction is suppressed, and the fluctuation of the suction force by the stator 33 is suppressed. The rate of pressure decrease can be stabilized.

Further, the electromagnetic valve 3 has a plate-like valve body 48 that fits into the tip of the movable element 32 and opens and closes the outlet 29.
Thereby, by adjusting the thickness of the valve body 48, the amount of movement of the valve body 48 when the outlet port 29 is opened can be varied.

The valve body 48 is a nonmagnetic material.
Thereby, delivery of the magnetic flux between the valve body 48 and the stator 33 can be suppressed, and the attraction force acting on the mover 32 can be prevented from being lowered.

  Further, the electromagnetic valve 3 has a stopper mechanism 43 that prevents contact between the mover side magnetic part 37 and the stator side magnetic part 42, and the stopper mechanism 43 is fixed to each of the stator 33 and the mover 32. The movable member side and stator side contact portions 44 and 45 are formed. The mover-side contact portion 44 is provided so as to protrude toward the rear end side, and the mover-side magnetic portion 37 and the stator-side magnetism are brought into contact with the mover-side and stator-side contact portions 44 and 45. Contact with the portion 42 is prevented.

  A soft magnetic material having a low hardness such as electromagnetic stainless steel, silicon steel, or low carbon steel is used for the material of the mover side magnetic part 37 and the stator side magnetic part 42 from the viewpoint of magnetic characteristics. For this reason, if the mover-side magnetic part 37 is brought into direct contact with the stator-side magnetic part 42, the wear of the mover-side and stator-side magnetic parts 37, 42 is accelerated. Therefore, the mover side and the stator side contact portions 44 and 45 are separately fixed to the stator 33 and the mover 32, respectively, and the material of the mover side and the stator side contact portions 44 and 45 is made of hardness. By using high alloy steel, stainless steel, or the like, it is possible to suppress the progress of wear of the mover side and stator side magnetic portions 37 and 42.

Further, the valve body 48 is made of a material having higher hardness than the mover side magnetic part 37 and the stator side magnetic part 42.
When the outlet 29 is opened, the fuel in the back pressure chamber 12 is pressure-reduced from a high pressure of several hundred MPa to an atmospheric pressure and flows out from the outlet 29. For this reason, the closing surface 50 of the valve body 48 may be heated and softened due to heat generation accompanying the pressure reduction of the fuel, and as a result, the sealing ability with respect to the outlet 29 may be reduced. Therefore, by providing the valve body 48 with a material having high hardness, it is possible to prevent softening due to heat from the fuel and to suppress a decrease in the sealing ability.

  The mover 32 is provided in a plate shape, and when the outlet 29 is opened, a moment due to the dynamic pressure of the fuel flowing out from the back pressure chamber 12, a moment due to the suction force of the stator 33, and a moment due to the biasing force of the coil spring 34. The moment due to the weight of the movable element 32 acts on the movable element 32. The suction force of the stator 33, the biasing force of the coil spring 34, and the weight of the movable element 32 all act on the movable element 32 when the outlet 29 is opened, even when the back pressure is the lowest pressure during actual use. Therefore, the movable element 32 is set so as to be directed to an ideal inclination state perpendicular to the axial direction.

  Thus, the movable element 32 can autonomously correct the inclination so as to be directed to an ideal inclination state when moving to open the outlet 29. For this reason, since the fluctuation | variation of a suction force can further be suppressed, the decreasing speed of a back pressure can be stabilized further.

In addition, the outlet port 29 opens to an opening surface 49 perpendicular to the axial direction, and the valve body 48 of the electromagnetic valve 3 has a closing surface 50 that contacts the opening surface 49 and closes the outlet port 29.
Thereby, the outflow port 29 is closed with the surface sheet | seat which utilizes the overlap of surfaces. For this reason, the structure which closes the outflow port 29 can be easily provided compared with the structure which closes the outflow port 29 with the wire sheet with respect to a taper surface, for example.

[Modification]
The aspect of the injector 1 is not limited to an Example, Various modifications can be considered.
For example, according to the injector 1 of the embodiment, the receiving surface 57 is provided so as to form a conical tapered recess, but is not limited to such a mode. That is, the receiving surface 57 may have any form as long as it is continuously reduced in diameter toward the tip side to form a recess. For example, the receiving surface 57 may be provided so as to form a semispherical recess. Good.

  Further, according to the injector 1 of the embodiment, the spring as the urging means for urging the movable element 32 in the direction opposite to the suction direction by the stator 33 is the coil spring 34. For example, a plate spring, a disc spring or the like may be used as the spring instead of the coil spring 34.

  Further, according to the injector 1 of the embodiment, the stopper mechanism 43 of the electromagnetic valve 3 is provided so that the movable element side contact portion 44 protrudes toward the rear end side toward the stator side contact portion 45. However, the stator-side contact portion 45 may protrude toward the front end side toward the mover-side contact portion 44, and the mover-side contact portion 44 is rearward toward the stator-side contact portion 45. The stator side contact portion 45 may protrude toward the distal end side toward the mover side contact portion 44.

  Further, according to the injector 1 of the embodiment, the outlet 29 of the back pressure chamber 12 is a surface sheet that uses the overlap of the surfaces of the closing surface 50 of the valve body 48 and the opening surface 49 at the rear end surface of the tip packing 6. However, for example, the outlet 29 may be closed by a line sheet with respect to the tapered surface.

  Further, according to the injector 1 of the embodiment, ceramic is exemplified as the material of the valve body 48, but a non-magnetic material and high hardness material other than ceramic may be used as the material of the valve body 48. A surface corresponding to the closing surface 50 of the magnetic material may be subjected to a hardening process such as a DLC process and used as the valve body 48.

  Further, according to the injector 1 of the embodiment, the back pressure is directly applied to the nozzle needle 9. For example, the command piston is supported in the main body 4 so as to be slidable in the axial direction. The back pressure chamber 12 may be formed on the rear end side of the command piston, and the back pressure may be applied to the nozzle needle 9 via the command piston.

1 Injector 3 Solenoid valve 8 Injection hole 9 Nozzle needle 12 Back pressure chamber 29 Outlet 31 Solenoid coil 32 Movable element 33 Stator 34 Coil spring (spring)
37 Mover-side magnetic part (magnetic part of the mover)
42 Magnetic part of the stator (magnetic part of the stator)
43 Stopper mechanism 44 Movable element side contact portion (movable element contact portion)
45 Stator side abutment (stator abutment)
48 Valve body 49 Opening surface (plane)
50 Closing surface 56 Sphere 57 Receiving surface

Claims (5)

A nozzle needle (9) for opening and closing the nozzle hole (8) is provided, and a back pressure chamber (12) for applying a fuel pressure to the nozzle needle (9) in a direction to close the nozzle hole (8) is formed. The nozzle hole (8) is closed or opened by varying the fuel pressure in the back pressure chamber (12) by increasing or decreasing the fuel pressure in the back pressure chamber (12). In the injector (1)
A solenoid valve (3) for opening and closing the fuel outlet (29) of the back pressure chamber (12);
The fuel pressure in the back pressure chamber (12) increases when the outlet (29) is closed by the solenoid valve (3) and decreases when the outlet (29) is opened.
The solenoid valve (3)
The mover (32) and the stator (33) that are excited by energizing the solenoid coil (31) and exert an attractive force in the axial direction, and the attracting direction of the mover (32) by the stator (33) A spring (34) biased in the opposite direction, interposed between the spring (34) and the mover (32), transmits a force between the spring (34) and the mover (32). A spherical body (56), and a plate-shaped valve body (48) that fits into the tip of the mover (32) to open and close the outlet (29),
The mover (32) is attracted toward the stator (33) in response to the start of energization of the solenoid coil (31), thereby opening the outlet (29) and the mover (32). Compresses the spring (34) via the sphere (56) by
By energizing the mover (32) via the sphere (56) by the spring (34) in response to the energization stop of the solenoid coil (31), the mover (32) is moved to the stator. (33) and closing the outlet (29),
The sphere (56) is slidably supported in the axial direction and is received by a receiving surface (57) provided on the mover (32).
The injector (1), wherein the receiving surface (57) is provided so as to form a recess having a diameter continuously reduced in a biasing direction by the spring (34). Injector (1) according to claim 1,
The injector (1), wherein the valve body (48) is a non-magnetic material. Injector (1) according to claim 1 or claim 2,
The electromagnetic valve (3) has a stopper mechanism (43) for preventing contact between the magnetic part (37) of the mover (32) and the magnetic part (42) of the stator (33),
The stopper mechanism (43) includes contact portions (44) and (45) fixed to the movable element (32) and the stator (33), respectively.
The contact portion (44) of the movable element (32) and the contact portion (45) of the stator (33) are provided so that at least one protrudes toward the other,
Due to the contact between the contact portion (44) of the movable element (32) and the contact portion (45) of the stator (33), the magnetic portion (37) of the movable element (32) and the stator ( 33) An injector (1) characterized in that contact with the magnetic part (42) of 33) is prevented. Injector (1) according to any one of claims 1 to 3,
The movable element (32) is provided in a plate shape,
When the outlet (29) is opened, the moment due to the dynamic pressure of the fuel flowing out from the back pressure chamber (12), the moment due to the suction force of the stator (33), the moment due to the biasing force of the spring (34), And a moment due to the weight of the mover (32) acts on the mover (32),
The suction force of the stator (33), the biasing force of the spring (34), and the dead weight of the mover (32) can be obtained even when the fuel pressure in the back pressure chamber (12) is the lowest pressure in actual use. The movable element (32) is set so as to be oriented in a direction perpendicular to the axial direction by all moments acting on the movable element (32) when the outlet (29) is opened. Injector (1). Injector (1) according to any one of claims 1 to 4,
The outlet (29) opens in a plane (49) perpendicular to the axial direction,
The injector (1), wherein the valve body (48) has a closing surface (50) that comes into surface contact with the flat surface (49) and closes the outlet (29).

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