JP6063894B2 - Fuel injection device - Google Patents

Description

  The present invention relates to a fuel injection device used in, for example, an internal combustion engine.

  For example, in Patent Document 1, the outer diameter of the fixed core opposite to the movable core has a large-diameter portion that is larger than the outer diameter of the movable core, and the opposite end surface facing the movable core of the fixed core is the fixed core. A magnetic member that is recessed radially inward from the large-diameter portion, and that the outer diameter of the opposed end surface of the fixed core is smaller than the outer diameter of the large-diameter portion, so that the opposed end surface of the fixed core is installed on the outer periphery of the movable core A fuel injection valve is disclosed in which the area facing the surface is reduced, the decrease in magnetic flux flowing between the fixed core and the movable core is reduced, and the attractive force is improved.

Japanese Patent Laid-Open No. 2005-207412

  An eddy current generated in the magnetic circuit is a factor that determines the dynamic responsiveness of the movable core. Eddy currents are generated in the direction that cancels the magnetic flux generated by supplying current to the coil, and even when the current supply to the coil is stopped, the eddy current is generated in the direction opposite to the direction in which the magnetic flux is canceled and always changes the magnetic field. Occurs in the direction of obstruction. In the electromagnetic fuel injection device, the magnetic flux is generated after the current is supplied to the coil until the attractive force rises, and the supply of the electric current to the coil is interrupted until the magnetic flux is reduced and the attractive force is reduced. This causes a problem of magnetic delay. For example, as in the fuel injection valve (fuel injection device) described in Patent Document 1, the outer diameter of the fixed core on the side opposite to the movable core is made larger than the outer diameter of the movable core, so that the magnetic path cross-sectional area of the fixed core is increased. Increases and the suction power is improved. On the other hand, by increasing the cross-sectional area of the magnetic path of the fixed core, the magnetic delay time from when the current is supplied to the coil until the magnetic flux rises and the time from when the current supply to the coil is stopped until the magnetic flux is cut off Magnetic lag time may increase. In the fuel injection valve described in Patent Document 1, consideration for the eddy current that determines the dynamic response is not always sufficient.

  An object of the present invention is to solve the above-described problems, and to provide a fuel injection device excellent in dynamic response.

  In the present invention, a magnetic aperture whose inner diameter increases toward the mover is provided on the inner peripheral surface of the magnetic core (fixed core).

  In a fuel injection device using an electromagnet, when current is supplied to a coil, magnetization starts from the outer peripheral surface side of the magnetic core located in the vicinity (inner peripheral surface side) of the coil due to the influence of eddy current, and is far from the coil Magnetization proceeds toward the inner peripheral surface of the magnetic core. On the other hand, when the current supply to the coil is stopped, demagnetization starts from the outer peripheral surface side of the magnetic core close to the coil. In the present invention, a magnetic aperture whose inner diameter increases toward the mover side is formed on the inner peripheral surface of the magnetic core (fixed core) by cutting the inner diameter side thickness of the end surface on the mover side of the magnetic core. By providing, the magnetic delay time at the time of valve opening from when the current is supplied to the coil until the magnetic flux rises and the magnetic time at the time of closing the valve until the magnetic flux decreases after the current supply to the coil is stopped The delay time can be shortened and the dynamic response at the time of opening and closing can be improved.

  Furthermore, the outer diameter of the magnetic core (fixed core) may be larger than the inner diameter of the portion surrounding the outer periphery of the mover in the nozzle holder. With such a configuration, it is possible to improve the magnetic attractive force by reducing the magnetic resistance of the magnetic core and improving the magnetic flux density of the attractive surface.

Specifically, it may be configured as follows.
(1) A valve body that closes the fuel passage by coming into contact with the valve seat and opens the fuel passage by moving away from the valve seat, a mover that performs an on-off valve operation in cooperation with the valve body, and energizing the coil And a magnetic core that generates a magnetic force that drives the mover by being excited by the magnetic core, the magnetic core is formed in a direction along the valve shaft that opens at an end surface facing the mover. have holes, the holes are pre-Symbol inner diameter toward the end face is formed large inner diameter portion to expand, the outer peripheral side than the insertion hole and the insertion hole in the movable element, wherein the valve body is inserted And the center of the insertion hole is located on the inner peripheral side of the inner diameter portion of the end surface of the magnetic core in which the inner diameter enlarged portion is formed, and the fuel passage hole has the inner diameter The end of the magnetic core on which the enlarged portion is formed It is formed at a position overlapping with the inner diameter part of the surface in the axial direction.
(2) Alternatively, the magnetic core has a hole formed in a direction along the valve shaft that opens to an end surface facing the mover, and the hole has an inner diameter expanding portion in which an inner diameter increases toward the end surface. The movable element is formed with an insertion hole into which the valve body is inserted and a fuel passage hole located on the outer peripheral side of the insertion hole, and the center of the fuel passage hole is the minimum diameter of the hole. The fuel passage hole is formed at a position overlapping in the axial direction with the inner diameter portion of the end face of the magnetic core in which the inner diameter enlarged portion is formed .
(3) In (1) or (2), the center of the fuel passage hole is located on the inner peripheral side of the inner diameter portion of the end face of the magnetic core in which the inner diameter enlarged portion is formed.
(4) In (1) or (2), the mover has a second hole formed in a direction along the valve axis that opens to an end surface opposite to the end surface facing the magnetic core, The second hole is formed with an inner diameter enlarged portion whose inner diameter increases toward the opposite end surface in a range of half or more in the axial direction of the second hole.
(5) In (1) or (2), the mover has a second hole formed in a direction along the valve shaft that opens to an end face opposite to the end face facing the magnetic core. The second hole has an inner diameter that increases toward the opposite end surface, and an inner diameter enlarged portion having a substantially linear tapered shape is formed.
(6) In (1) or (2), the starting point position in the radial direction of the inner diameter enlarged portion formed in the second hole is determined from the inner diameter portion of the end face of the magnetic core on which the inner diameter enlarged portion is formed. Also on the outer peripheral side.
(7) In (1) or (2), the valve body and the movable element are configured as separate members so as to be capable of relative displacement, and the valve body is a relative displacement in the valve opening direction of the movable element with respect to the valve body. The portion where the inner diameter of the hole formed in the magnetic core is minimized is formed closer to the fuel inlet than the position of the restricting portion.

  ADVANTAGE OF THE INVENTION According to this invention, the fuel-injection apparatus excellent in the dynamic response can be provided.

It is a longitudinal cross-sectional view of the fuel-injection apparatus of one Example which concerns on this invention. It is an enlarged view of the drive part cross section of the fuel-injection apparatus of 1st Example of this invention. It is the enlarged view C of the outer diameter side lower surface part of the needle | mover in FIG. It is an enlarged view of the contact part A of the nozzle holder upper end surface and magnetic core in FIG. It is an enlarged view of the drive part cross section of the fuel-injection apparatus of the 2nd Example of this invention. It is an enlarged view of the magnetic core outer peripheral part B in FIG. It is an enlarged view of the contact part E of the nozzle holder upper end surface and magnetic core in FIG. It is an enlarged view of the drive part cross section of the fuel-injection apparatus in the 3rd Example of this invention. It is an enlarged view of the magnetic core outer peripheral part D in FIG. It is an enlarged view of the drive part cross section of the fuel-injection apparatus in 4th Example of this invention. It is an enlarged view of the drive part cross section of the fuel-injection apparatus in 5th Example of this invention. It is an enlarged view of the needle | mover inner diameter part F in FIG. It is an enlarged view of the drive part cross section of the fuel-injection apparatus of 6th Example of this invention. It is an enlarged view of the drive part cross section of the fuel-injection apparatus of 7th Example of this invention. It is an enlarged view of the drive part structure of the fuel-injection apparatus in the 8th Example of this invention. It is an enlarged view of the drive part structure of the fuel-injection apparatus in 9th Example of this invention. It is an enlarged view of the drive part structure of the fuel-injection apparatus in the 10th Example of this invention.

  The operation and configuration of the fuel injection device according to the embodiment of the present invention will be described below with reference to FIGS.

  First, the configuration and operation of the fuel injection device according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a longitudinal sectional view showing an embodiment of the fuel injection device of the present invention.

  In this embodiment, the movable element (movable core) 102 is not fixed to the valve body 114 and is assembled to the valve body 114 so as to be relatively displaceable in the valve shaft direction. The relative displacement of the movable element 102 in the valve opening direction is restricted by a restricting portion (stopper portion) 114 a of the valve body 114. The restricting portion 114a is formed by an enlarged diameter portion having a larger diameter than the valve needle portion 114c of the valve body 114. The movable element 102 is provided on the other end side with respect to the restricting portion 114a, and relative displacement toward the contact portion (seat portion 114b) that contacts the valve seat 118, that is, relative displacement in the valve closing direction is restricted by the valve body 114. It will never be done.

  The fuel injection device in FIG. 1 configured as described above is a normally closed electromagnetic fuel injection device, and the valve body 114 is closed by a spring (first spring) 110 when the coil 105 is not energized. Energized in the valve direction, the valve seat 118 is in close contact with the valve seat 118. In this closed state, the mover 102 is brought into close contact with the restricting portion 114a of the valve body 114 by a zero spring (second spring) 112, and there is a gap between the mover 102 and the magnetic core (fixed core) 107. doing. The fuel is supplied from a fuel supply port 123 provided in the upper part of the fuel injection device, and the fuel is sealed by a valve seat 118. When the valve is closed, the force by the spring 110 and the force by the fuel pressure act on the valve body 114 in the valve closing direction, and the valve body 114 is pushed in the valve closing direction. The end of the spring (first spring) 110 opposite to the end in contact with the valve body 114 is in contact with the adjuster pin 120, and the spring force of the spring 110 is adjusted by the adjuster pin 120.

  A magnetic circuit for generating an electromagnetic force for the on-off valve includes a magnetic core 107, a mover 102, at least a part of the magnetic core 107 on the mover 102 side, and the mover 102. The nozzle holder 101 which is the cylindrical member arrange | positioned in this and the housing 103 are comprised. The housing 103 has a radially extending portion 103 a extending in the radial direction at the lower end thereof, and the inner peripheral surface 103 b of the radially extending portion 103 a faces the outer peripheral surface 102 a of the mover 102 in the nozzle holder 101. It is in contact with the outer peripheral surface of the portion 101a. The housing 103 surrounds the outer periphery of the coil 105, and the inner peripheral surface of the portion 103 c that is higher than the coil 105 is in contact with the outer peripheral surface of the flange portion 107 a of the magnetic core 107. The housing 103 constitutes a yoke portion of the magnetic circuit.

  When a current is supplied to the coil 105, a magnetic flux is generated in the magnetic circuit, and a magnetic attractive force is generated between the movable element 102, which is a movable part, and the magnetic core 107, which is a fixed part. When the magnetic attractive force acting on the mover 102 exceeds the sum of the load applied by the spring 110 and the force acting on the valve body 114 due to the fuel pressure, the mover 102 moves upward. At this time, the valve body 114 moves upward together with the movable element 102 and moves until the upper end surface of the movable element 102 collides with the lower surface of the magnetic core 107. As a result, the seat 114b of the valve body 114 is separated from the valve seat 118, and the supplied fuel is injected from the plurality of injection ports 119. In addition, the number of holes of the injection port 119 may be a single hole. The injection port 119 and the valve seat 118 are formed in an orifice cup 116 attached to the tip of the nozzle holder 101. A plunger rod guide 115 for guiding the valve body 114 is provided on the upstream side of the orifice cup 116.

  Next, after the upper end surface 102b of the mover 102 collides with the lower surface (end surface on the mover side) 206 of the magnetic core 107, the restricting portion 114a of the valve body 114 is detached from the mover 102 and overshoots, but a certain amount After a period of time, the valve body 114 stops on the movable element 102 when the restricting portion 114a comes into contact with the movable element 102. When the supply of current to the coil 105 is cut off, the magnetic flux generated in the magnetic circuit is reduced and the magnetic attractive force is reduced. When the magnetic attraction force becomes smaller than the combined force of the load by the spring 110 and the fluid force received by the valve body 114 and the mover 102 due to the fuel pressure, the mover 102 and the valve body 114 move downward, and the valve body 114 moves. At the time of collision with the valve seat 118, the restricting portion 114 a of the mover 102 is detached from the valve body 114. On the other hand, the valve body 114 stops after colliding with the valve seat 118, and fuel injection stops.

  The movable element 102 and the valve body 114 may be integrally formed as the same member that is not relatively displaced, or may be configured as separate members so as not to be relatively displaced by a method such as welding or press-fitting. In the case where the movable element 102 and the valve body 114 are the same member that is not relatively displaced, the zero spring 112 is not necessary in terms of configuration. Even if it is such a structure, the effect of this invention does not change.

  Next, the configuration of the first embodiment of the present invention will be described with reference to FIGS. 2 is an enlarged view of a cross section of the drive unit of the fuel injection device in FIG. 1, and FIG. 3 is an enlarged view of the outer diameter side lower surface portion C of the mover 102 in FIG. 4 is an enlarged view of a contact portion A between the upper end surface of the nozzle holder 101 and the magnetic core 107 in FIG. 2, 3, and 4, the same reference numerals are given to the same components as those in FIG. 1.

  In the fuel injection device according to the present invention, when a current is supplied to the coil 105, a magnetic flux is generated in a magnetic circuit composed of the magnetic core 107, the mover 102, the housing 103, and the nozzle holder 101. A magnetic attractive force is generated between the child 102. The magnetic flux passing through the magnetic core 107 is a magnetic flux flowing toward the nozzle holder 101 at the position of the end face 206 of the magnetic core 107 on the movable element 102 side, and the magnetic core 107 attracting surface side, that is, between the magnetic core 107 and the movable element 102. The magnetic flux is distributed to the magnetic flux flowing between them. At this time, the number of magnetic fluxes passing between the magnetic core 107 and the mover 102 and the magnetic flux density determine the magnetic attractive force.

In the present embodiment, an inner diameter enlarged portion 201 whose inner diameter increases toward the attraction surface is provided on the inner diameter side of the mover side end surface 206 of the magnetic core 107. The magnetic core 107 is formed with a through hole 210 penetrating in the central portion of the magnetic core 107 in the valve shaft direction, and the through hole 210 constitutes a fuel passage. The inner diameter enlarged portion 201 is formed in the vicinity of the outlet portion of the through-hole 210 and is formed such that the inner diameter gradually decreases from the mover side end face 206 toward the upstream side in the fuel flow direction. With this effect, the area of the mover side end surface 206 is reduced by securing the cross-sectional area of the portion where the magnetic flux far from the mover side end surface 206 from the mover side end surface 206 of the magnetic core 107 passes. The magnetic flux density of the surface can be increased, and the magnetic attractive force can be improved. The inner diameter enlarged portion 201 expands as the magnetic gap in the direction along the valve axis with the mover 102 decreases as the inner diameter of the inner diameter enlarged portion 201 becomes smaller, that is, as it approaches the radial center of the magnetic core 107. It may be configured to do so. This is because the size of the magnetic gap (interval in the valve axis direction) between the magnetic core 107 and the mover 102 in the inner diameter enlarged portion 201 is the size of the magnetic gap between the mover side end face 206 and the mover 102. This is to increase the magnetic resistance. Thereby, the magnetic flux can reduce the magnetic flux which passes the internal diameter expansion part 201, can increase the magnetic flux which passes the needle | mover side end surface 206, and can raise the magnetic flux density of the needle | mover side end surface 206. Further, if the height L _A between the lower surface 207 of the magnetic core 107 located on the upper side of the coil 105 and the upper end of the inner diameter enlarged portion 201 is set larger than the height L _B of the inner diameter enlarged portion 201 in the valve axis direction, the effect is great. . By setting in this way, it is easy to obtain the effect of increasing the magnetic flux density by reducing the attraction surface while securing the magnetic path cross-sectional area of the magnetic core 107 located on the inner diameter side of the coil 105, and the attraction force can be improved. . Note that the inner diameter enlarged portion 201 may be configured with a taper, for example.

  When the inner diameter enlarged portion 201 is configured with a taper, for convenience of processing, it is preferable to provide a taper having a different angle from the taper of the inner diameter enlarged portion 201 at the upstream portion and the downstream portion of the inner diameter enlarged portion 201. In this case, it can also be said that the inner diameter enlarged portion 201 is constituted by a three-stage tapered portion. Then, the angle θ formed with the valve shaft center 209 is increased as the tapered portion is located on the downstream side. Due to this effect, processing burrs are less likely to occur at the upstream and downstream portions of the inner diameter enlarged portion 201, and the processing cost can be reduced.

  When a current is supplied to the coil 105, the magnetization proceeds from the inside of the coil to the outside due to the influence of the eddy current. On the other hand, when the current supply to the coil 105 is stopped, the magnetic flux disappears from a position close to the coil 105. When the current supply is stopped from the state where the current is supplied to the coil 105, the magnetic flux remains to the end on the inner diameter side of the magnetic core 107 located away from the coil 105. Therefore, even if the current supply to the coil 105 is stopped, there is a magnetic delay time until the magnetic attractive force decreases, and this magnetic delay time becomes a factor that deteriorates the responsiveness when the valve is closed. . Therefore, the magnetic delay time can be shortened by narrowing the width in the direction of magnetization in the magnetic material.

  In the present invention, the inner diameter enlarged portion 201 is provided in the magnetic core 107 so that the thickness of the end face 206 on the mover side of the magnetic core 107 is reduced. That is, the magnetic material on the inner peripheral side (inner diameter side) of the magnetic core 107 is scraped by the inner diameter enlarged portion 201, and the thickness of the magnetic core 107 is reduced accordingly. Due to this effect, the magnetic delay time at the time of valve opening until the magnetic flux rises after the current is supplied to the coil 105 and the magnetism at the time of valve closing until the magnetic flux decreases after the current supply to the coil 105 is stopped. The delay time can be shortened, and the responsiveness at the time of opening and closing can be improved. For the above reasons, according to the first embodiment of the present invention, it is possible to achieve both the magnetic attractive force and the dynamic response improvement.

  Here, in the configuration in which the cylindrical nozzle holder 101 is provided outside the magnetic core 107, the distance from the coil 105 to the magnetic core 107 is increased by the thickness of the nozzle holder 101. As the distance between the coil 105 and the magnetic core 107 increases, the speed at which magnetization proceeds and the speed at which demagnetization proceeds due to the influence of eddy currents slows, and dynamic responsiveness deteriorates. Therefore, the effect of the inner diameter enlarged portion 201 of the magnetic core 107 that can reduce the influence of eddy current becomes remarkable.

Further, since the inner diameter enlarged portion 201 provided in the magnetic core 107 is configured to increase the inner diameter in the downstream direction, a fluid passage can be secured between the magnetic core 107 and the valve body 114. When the mover 102 and the valve body 114 are configured as separate members so as to be capable of relative displacement, the inner diameter enlarged portion 201 is limited by the restricting portion provided on the valve body 114 from the mover side end face 206 of the magnetic core 107. (Stopper part) It is good to comprise to an upstream part rather than 114a. This effect makes it possible to ensure a sufficient fluid passage between the valve body 114 and the magnetic core 107. The fuel passing between the valve body 114 and the magnetic core 107 passes through the fuel passage hole 203 provided in the mover 102 and flows in the downstream direction. The center position of the fuel passage hole 203, by arranging the outer side than the inner diameter d _c of the magnetic core 107, it is possible to secure the fluid passage area of the fuel passing through the armature 102. In addition, the center position of the fuel passage hole 203 of the mover 102 is preferably arranged on the inner diameter side of the inner diameter of the mover side end face 206 of the magnetic core 107. Since the outer diameter side of the magnetic core 107 is closer to the outer diameter than the inner diameter of the mover-side end face 206, the magnetic flux cross-sectional area of the mover 102 is determined by defining the center position of the fuel passage hole 203. There is an effect of suppressing the reduction by the fuel passage. The fuel passage hole may be provided in the valve body 114 instead of the mover 102.

  Further, it is preferable to set the inner diameter of the plane portion of the magnetic core 107 facing the magnetic core 107 to be smaller than the inner diameter of the end face 206 of the magnetic core 107. Due to this effect, even when the mover 102 is decentered from the center position, the attraction area is determined by the end face 206 on the mover side of the magnetic core 107, so that variations in magnetic attraction force can be suppressed. By this effect, it is possible to suppress variations in the injection amount for each injection and variations in the injection amount due to individual differences.

  Further, the position of the magnetic gap between the magnetic core 107 and the mover 102 in the valve axis direction is determined by the coil 105 and the bobbin 104 when the mover 102 comes into contact with the restricting portion 114a of the valve body 114 and is stationary. It is good to overlap with the position in the valve-axis direction of the coil space comprised. This is because when the magnetic gap is below the coil space, the area of the side surface of the movable element 102 cannot be sufficiently obtained. Since there is a gap between the side surface of the mover 102 and the nozzle holder 101, the magnetic resistance of the side surface of the mover 102 tends to increase. In order to reduce the magnetic resistance of this portion, it is necessary to increase the side area for the passage of magnetic flux. For this reason, it is necessary to increase the area of the side surface of the movable element 102, that is, the height of the movable element 102. Therefore, by setting the axial position of the magnetic gap in the coil space, even if the height of the movable element 102 is sufficiently ensured, the side surface of the movable element can be brought closer to the inner diameter portion of the housing 103. Can be improved.

  Further, as shown in FIG. 4, a relief portion 150 for press-fitting with the magnetic core 107 may be configured on the inner diameter side of the upper end surface of the nozzle holder 101. When the nozzle holder 101 and the magnetic core 107 are assembled by a method such as press-fitting, a machining R is generated at the corner of the magnetic core 107 that is in contact with the upper end surface of the nozzle holder 101. There is a need. By providing the escape portion 150 in the nozzle holder 101 instead of the magnetic core 107, the magnetic path cross-sectional area of the magnetic core 107 is suppressed from being reduced by the escape for press-fitting, and the attractive force can be improved. In general, a material having inferior magnetic properties must be used for the nozzle holder 101 that requires strength. However, by providing a relief on the nozzle holder 101 side in this way, the magnetic core 107 having excellent magnetic properties can be used. There is no need to reduce the cross-sectional area, which is advantageous. In addition, the escape part 150 provided in the nozzle holder 101 is good to comprise a taper, for example.

  Here, on the surface (back surface) opposite to the end surface facing the magnetic core 107 of the mover 102, an inner diameter enlarged portion 205 whose inner diameter increases in the outer diameter direction may be provided. Here, if the thickness of the inner diameter portion of the mover 102 is increased for the purpose of securing a magnetic path cross-sectional area for improving the attractive force, the mass increases, and the acceleration of the mover 102 at the time of opening / closing becomes small. Therefore, the time required for the on-off valve increases. Therefore, in the mover 102, it is desirable to ensure both the magnetic path cross-sectional area and the mass reduction.

  In the configuration of the magnetic core 107 and the mover 102, the outer diameter side of the mover side end face 206 of the magnetic core 107 is the main path through which the magnetic flux of the mover 102 passes. It is necessary to arrange the magnetic body so that the magnetic path cross-sectional area can be secured. Accordingly, by configuring the start point 208 of the inner diameter enlarged portion 205 provided in the mover 102 to be located on the outer diameter side of the inner diameter of the mover side end surface 206 of the magnetic core 107, the necessary magnetic force of the mover 102 is obtained. The mass can also be reduced while securing the road cross-sectional area. In the present invention, since the inner diameter enlarged portion 201 is provided in the magnetic core 107, the volume of the inner diameter enlarged portion 205 can be suppressed to the minimum necessary, and the mass of the mover 102 can be reduced.

  Further, as shown in FIG. 3, a lower inner diameter surface 303 that is a peripheral surface parallel to the valve shaft center is provided below the inclined surface 302 of the mover 102, and the outer peripheral surface of the mover 102 facing the lower inner diameter surface 303. A recess 301 is preferably provided on the surface. Here, in the fuel injection device in which the magnetic core 107 and the mover 102 are in contact, the contact surface between the magnetic core 107 and the mover 102 may be plated with chromium or the like in order to increase the durability of the collision surface. When the movable element 102 is plated, a groove for fixing the position of the movable element 102 is required on the outer diameter surface. However, since the outer diameter of the mover 102 is a magnetic path through which the magnetic flux passes, if the position of the recess 301 of the mover 102 is configured on the upper part of the mover 102, the outer diameter of the mover 102 and the nozzle holder 101 In the meantime, there is a problem that the magnetic resistance increases and the attractive force decreases. According to the above configuration, a reduction in suction force is suppressed, and the plating process of the mover 102 is facilitated.

  A second embodiment according to the present invention will be described with reference to FIGS. FIG. 5 is an enlarged view of a drive section of the fuel injection device in the second embodiment, and FIG. 6 is an enlarged view of an outer peripheral portion B of the magnetic core in FIG. FIG. 7 is an enlarged view of the upper end surface of the nozzle holder and the magnetic core contact portion E in FIG. 5, 6 and 7, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals.

  In the example shown in FIGS. 5 and 6, in addition to the first embodiment, the nozzle holder 101 is provided with an inner diameter large diameter portion 605 having a large inner diameter and an inner diameter small diameter portion 606 having a small inner diameter. Thereby, the outer diameter of the magnetic core 107 becomes larger than the inner diameter small diameter portion 606 of the nozzle holder 101. Here, from the geometric relationship of the cross-sectional area, securing the cross-sectional area of the magnetic core 107 disposed on the inner diameter side of the coil 105 secures the cross-sectional area of the housing 103 disposed on the outer diameter side of the coil 105. More difficult to do. Therefore, the magnetic core 107 is magnetically saturated earlier than the housing 103 because the magnetic core 107 has a small magnetic path cross-sectional area. Therefore, in this embodiment, by making the outer diameter of the magnetic core 107 larger than the inner diameter small diameter portion 606 of the nozzle holder 101, it is easy to ensure the radial cross-sectional area of the magnetic core 107. Further, the area of the end surface 604 on the mover side of the magnetic core 107 may be configured to be 10% or more smaller than the cross-sectional area of the magnetic core 107 upstream of the inner diameter enlarged portion 201. This has the effect of suppressing the magnetic core 107 from reaching the saturation magnetic flux density, and the number of magnetic fluxes generated in the magnetic circuit can be increased by lowering the magnetic flux density of the magnetic core 107.

  Further, when a soft magnetic material is used for the magnetic core 107, the area of the magnetic core 107 mover side end surface 604 is configured to be reduced by 10% or more compared to the cross-sectional area at the upstream position from the inner diameter enlarged portion 201. Good. In a general soft magnetic material, when the magnetic flux density is about 10% smaller than the saturation magnetic flux density, the magnetic saturation state is lost and the magnetic permeability increases. Therefore, since the magnetic core 107 has a cross-sectional area larger than the area of the mover side end surface 604 of the magnetic core 107, the magnetic flux density of the portion other than the attraction surface of the magnetic core 107 can be suppressed, and the magnetic core 107 can be attracted with a high permeability. Only the surface can be brought close to the saturation magnetic flux density. Due to this effect, the magnetic resistance of the magnetic core 107 is reduced, and the attractive force can be increased. The outer diameter of the mover side end surface 604 of the magnetic core 107 is preferably larger than the inner diameter small diameter portion 606 of the nozzle holder 101. This is because the magnet is magnetized from the inner diameter side of the coil 105 due to the influence of the eddy current. Therefore, by reducing the distance between the magnetic core 107 and the coil 105, the speed of magnetization is promoted and the dynamic response is improved. It is.

Further, as shown in FIG. 6, the nozzle holder 101 has a switching position 607 for switching from the inner diameter large diameter portion 605 to the inner diameter small diameter portion 606. The axial gap h _g between the switching position 607 and the mover side end surface 604 of the magnetic core 107 is such that the valve core 114 and the mover 102 are stationary in the closed state, and the magnetic core 107 and the mover 102 are stationary. It may be set larger than the distance _Hst . This is because magnetic flux tends to leak from the mover side end surface 604 of the magnetic core 107 to the switching position 607 by making the outer diameter of the magnetic core 107 larger than the inner diameter small diameter portion 606 of the nozzle holder 101. By setting the gap h _{g in} this way, the magnetic flux flowing from the mover side end surface 604 of the magnetic core 107 to the switching position 607 of the nozzle holder 101 can be minimized. That is, the magnetic flux flowing between the magnetic core 107 and the mover 102 can be increased, and the magnetic attractive force can be improved. In addition, the shape of the switching position 607 of the nozzle holder 101 shows a planar example in FIG. By making it flat like this, the range in which the inner diameter small diameter portion 606 of the nozzle holder 101 is close to the side surface of the mover 102 can be increased, and the magnetic resistance between the mover 102 and the inner diameter small diameter portion 606 is increased. Since it becomes small, it becomes easy to obtain a large magnetic attraction force. However, the switching position may be a shape including a taper or a curvature that decreases in inner diameter toward the downstream.

The distance Δr between the small inner diameter portion 606 and the large inner diameter portion 605 may be configured to be larger than the gap S _g between the mover 102 and the small inner diameter portion 606 of the nozzle holder 101. Distance Δr to be to be larger than the gap S _g, it is possible to reduce the gap S _g, it is possible to reduce the magnetic resistance between the armature 102 and the nozzle holder 101. This effect can improve the magnetic attractive force.

  Further, as shown in FIG. 5 and FIG. 7, the magnetic core 107 located on the inner diameter side of the coil 105 with respect to the magnetic path cross-sectional area of the magnetic core 107 located on the outer side of the coil 105 from the geometrical relationship of dimensions. It is difficult to secure a cross-sectional area of Therefore, when providing relief in the magnetic core 107, if the magnetic core 107 is provided not on the cylindrical surface 172 that contacts the inner diameter of the nozzle holder 101 but on the contact surface 171 that contacts the upper end surface of the nozzle holder 101, such as the escape portion 170. Good. Due to this effect, it is possible to suppress a reduction in the magnetic path cross-sectional area of the magnetic core 107 and improve the magnetic attractive force.

Half of the difference between the opening diameter d (diameter of the fuel passage 210) the inner diameter of _a magnetic core 107 d _c of the large inner diameter portion 201, i.e. the radius of the through holes 210a of the opening of the radius and the magnetic core 107 of the large inner diameter portion 201 The difference Δd is larger than the distance Δr between the small inner diameter portion 606 and the large inner diameter portion 605. Δd is also the distance in the radial direction (direction perpendicular to the valve axis) between the opening circle of the inner diameter enlarged portion 201 and the inner circumferential circle of the magnetic core 107. A taper portion of the inner diameter enlarged portion 201 is provided in the range of the interval in the radial direction. In order to make the area of the portion sandwiched between two circles having different radii the same at a radius position far from the center of the circle and a radius position near the circle, the radius position far from the center of the circle is closer. The difference in radius between the two circumferences can be made smaller than in the case of the radial position. Therefore, in the case where the outer surface of the magnetic core 107 compensates for the area that decreases because the inner diameter enlarged portion 201 is provided on the end surface of the magnetic core 107 facing the mover 102, Δr may be smaller than Δd. In other words, it is necessary to increase Δd with respect to Δr that can be secured.

  A third embodiment of the present invention will be described with reference to FIGS. FIG. 8 is an enlarged view of a cross section of the drive unit of the fuel injection device according to the third embodiment of the present invention, and FIG. 9 is an enlarged view of the outer periphery D of the magnetic core in FIG. 5 and 9, the same components as those in FIGS. 1, 2, 5, and 6 are denoted by the same reference numerals.

  In the example shown in FIGS. 8 and 9, in addition to the second embodiment, an outer diameter small diameter portion 908 smaller than the outer diameter of the nozzle holder 101 is provided on the outer peripheral surface of the nozzle holder 101, and in contact with the magnetic core 107. A magnetic aperture portion 909 is configured by the inner diameter large diameter portion 605 and the outer diameter small diameter portion 908 of the nozzle holder 101. The outer diameter / small diameter portion 908 forms an annular recess (groove) formed on the outer peripheral surface of the nozzle holder 101 so as to surround the valve shaft center. By providing the magnetic restrictor 909 in the nozzle holder 101, the magnetic flux flowing through the nozzle holder 101 can be reduced, and the magnetic flux flowing between the magnetic core 107 and the mover 102 can be increased. The magnetic attractive force can be improved by increasing the magnetic flux. Further, the magnetic flux flowing through the magnetic core 107 and the nozzle holder 101 is distributed at the position of the mover side end surface 604 of the magnetic core 107 into the magnetic flux flowing to the mover 102 and the magnetic flux flowing to the magnetic restrictor 909 of the nozzle holder 101. The Here, the magnetic flux flowing through the magnetic restricting portion 609 can be suppressed by setting the position of the outer diameter small diameter portion 908 in the valve axis direction on the extension of the mover side end surface 604 of the magnetic core 107 in the outer diameter direction. In addition, since a large amount of magnetic flux can flow toward the movable element 102, the attractive force can be improved. Further, since the magnetic diaphragm 909 can be reduced by reducing the magnetic path cross-sectional area of the magnetic diaphragm 909, the magnetic diaphragm 909 is magnetically saturated after the current is supplied to the coil 105. It is possible to shorten the time to do. By this effect, the speed at which magnetization proceeds toward the inner diameter side of the magnetic core 107 and the mover 102 can be increased, and the dynamic responsiveness of the attractive force can be improved.

  A fourth embodiment according to the present invention will be described with reference to FIG. FIG. 10 is an enlarged view of a cross section of the drive unit of the fuel injection device according to the present invention. 10, the same components as those in FIGS. 1, 2 and 6 are denoted by the same reference numerals.

  In the example shown in FIG. 10, in addition to the second embodiment, a plurality of tapers of a first taper 701 and a second taper 702 are provided on the inner diameter side of the magnetic core 107. Here, in the fuel injection device according to the present invention, since the inner diameter of the magnetic core 107 is used as the fuel passage, it is necessary for the magnetic path cross-sectional area of the magnetic core 107 and the fuel passage necessary for improving the attractive force. It is desirable to ensure the cross-sectional area of the fuel passage between the valve body 114 and the magnetic core 107. For the above reasons, by switching the taper angle provided on the inner diameter of the magnetic core 107, the first taper 701 ensures a magnetic path cross-sectional area at a position away from the mover side end surface 604 of the magnetic core 107. The second taper 702 can increase the cross-sectional area of the fuel passage in the downstream direction, which facilitates the design of the fuel injection device.

  A fifth embodiment according to the present invention will be described with reference to FIGS. FIG. 11 is an enlarged view of a cross section of the drive portion of the fuel injection device in the fifth embodiment, and FIG. 12 is an enlarged view of the inner diameter portion F of the mover 102 in FIG. 11 and 12, the same components as those in FIGS. 1, 2 and 6 are denoted by the same reference numerals.

In the example shown in FIG. 11, in addition to the second embodiment, an inner diameter enlarged portion 801 having an inner diameter enlarged portion 201 whose inner diameter expands toward the attracting surface on the inner circumferential surface of the magnetic core 107 and having a shape including a curvature, did. Here, the cross-sectional area of the fuel passage on the inner diameter side of the magnetic core 107 is the smallest between the restricting portion 114 a provided in the valve body 114 and the magnetic core 107. By the magnetic diaphragm provided on the inner diameter side of the magnetic core 107 in a shape that includes a curvature such as the inner diameter enlarged portion 801, changes the internal diameter d _a of the magnetic core 107 of the portion where the fuel passage cross-sectional area is most reduced Without doing so, the magnetic path cross-sectional area of the upstream and downstream magnetic cores 107 can be increased. As a result, the number of magnetic fluxes that can be generated in the magnetic core 107 increases, and the attractive force can be improved.

  Further, it is desirable that the gap between the movable element 102 and the inner diameter of the nozzle holder 101 has a gap that does not come into contact even when the movable element 102 is inclined. This is because, when the movable element 102 and the nozzle holder 101 come into contact with each other, the frictional resistance received by the movable element 102 increases, and the responsiveness of the on-off valve decreases.

  Further, the movable element 102 is provided with a sliding extension 810 that extends a sliding surface that contacts the valve body 114. Here, the inclination of the movable element 102 with respect to the valve body 114 is determined by the gap and the sliding height between the sliding portions of the movable element 102 and the valve body 114. In this embodiment, by providing the sliding extension 710 on the movable element 102, the sliding height between the valve body 114 and the movable element 102 is extended, and the inclination and eccentricity of the movable element 102 with respect to the valve body 114 can be suppressed. Due to this effect, the gap between the mover 102 and the nozzle holder 101 can be reduced, and the magnetic resistance of the outer diameter portion of the mover 102 is reduced, so that the magnetic attractive force can be improved. Further, when the mover 102 is eccentric, the flow rate flowing between the outer diameter of the mover 102 and the inner diameter of the nozzle holder 101 increases, and the fluid resistance received by the mover 102 changes. Due to this change in fluid resistance, the behavior of the mover 102 is different for each injection, and the injection amount variation becomes large. For the above reasons, providing the sliding extension 810 can suppress the eccentricity of the mover 102 and reduce the variation in the injection amount. The sliding extension 810 may be provided on the inner diameter side of the fuel passage provided in the movable element 102. Thereby, since the increase in the mass of the needle | mover 102 by providing the sliding extension part 810 can be suppressed, the fall of the responsiveness at the time of opening and closing can be suppressed.

  A sixth embodiment according to the present invention will be described with reference to FIG. FIG. 13 is an enlarged view of the drive unit structure of the fuel injection device in the sixth embodiment. In FIG. 13, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals.

  In the example shown in FIG. 13, in addition to the second embodiment, the movable element 102 and the valve body 114 are made of the same member. Although the movable element 102 and the valve body 114 may be configured by combining different members, it is sufficient that the movable element 102 and the valve body 114 can be configured as the integrated member 130. By using the integral member 130, the number of parts can be suppressed, and the cost can be reduced. Further, in the structure in which the movable element 102 and the valve body 114 are separated, the movable element 102 is detached from the valve body 114 when the valve body 114 collides with the valve seat 118 when the valve is closed. Due to the collision between the valve body 114 and the valve seat 118, the valve body 114 can be prevented from bouncing and secondary fuel injection occurring. On the other hand, when the valve body 114 collides with the valve seat 118, the movable element 102 is detached from the valve body 114 and moves downward, so that there is a demerit that the time until the movable element 102 stops becomes longer. The time until the mover 102 stops depends on the balance of the mass of the mover 102, the speed at the time of the collision between the valve body 114 and the valve seat 118, the spring force of the zero spring 112 and the force of the fluid force received by the mover 102. To do. If the next injection is performed before the mover 102 stops, the time from when the valve body 114 starts to move until it opens will vary, making it difficult to accurately manage the injection amount. According to the present embodiment, since the time from when the valve element 114 collides with the valve seat 118 when the valve is closed until the movable element 102 stops can be shortened, the time until the next injection can be shortened. , Improve responsiveness.

  A seventh embodiment according to the present invention will be described with reference to FIG. FIG. 14 is an enlarged view of the drive unit structure of the fuel injection device in the seventh embodiment. In FIG. 14, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals.

  In the example shown in FIG. 14, in addition to the second embodiment, a fuel passage center hole 140 that is a fuel passage hole is provided in the valve body 114, and a groove 190 is provided in the end face on the magnetic core 107 side of the mover 102. . By providing the groove 190, the area of the end surface on the magnetic core 107 side of the mover 102 is reduced, so that the magnetic flux density on the attraction surface increases and the attraction force can be improved. For example, the groove 190 may be an annular shape.

  In this embodiment, the fuel passage center hole 140 is provided at the center position of the valve body. With such a configuration, since it is not necessary to secure a fuel passage between the magnetic core 107 and the valve body 114, the magnetic path cross-sectional area of the magnetic core 107 can be increased and the attractive force can be improved. Further, since the mass of the valve body 114 becomes small, the impact force when the valve body 114 collides with the valve seat 118 when the valve is closed can be reduced, and the bounce generated after the valve body 114 collides with the valve seat 118 can be reduced. Secondary fuel injection caused by the bounce can be suppressed.

  The eighth embodiment according to the present invention will be described with reference to FIG. FIG. 15 is an enlarged view of the drive unit structure of the fuel injection device in the eighth embodiment. In FIG. 15, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals.

In the example shown in FIG. 15, in addition to the second embodiment, larger inner diameter than the inner diameter d _c of the magnetic core 107 in the upstream portion of the taper 181 provided for the purpose of reducing the thickness of the inner diameter of the magnetic core 107 is large The diameter portion 180 is provided. With this effect, leakage of magnetic flux from the magnetic core 107 to the spring 110 can be reduced, and the attractive force can be improved. In addition, since the fuel core has a fluid passage between the magnetic core 107 and the valve body 114, providing the large diameter portion 180 has an effect of expanding the fluid passage.

  A ninth embodiment according to the present invention will be described with reference to FIG. FIG. 16 is an enlarged view of the drive unit structure of the fuel injection device in the ninth embodiment. In FIG. 16, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals.

  In the example shown in FIG. 16, in addition to the second embodiment, an inner diameter enlarged portion 550 is provided on the inner diameter of the magnetic core 107. In this embodiment, the inner diameter enlarged portion 550 is not a simple taper shape, but a stepped shape having at least two step surfaces. With this step-like shape, an effect similar to that of a tapered shape can be obtained. In this embodiment, there are three stages.

  A tenth embodiment according to the present invention will be described with reference to FIG. FIG. 17 is an enlarged view of the drive unit structure of the fuel injection device in the tenth embodiment. In FIG. 17, the same components as those in FIGS. 1, 2, and 11 are denoted by the same reference numerals.

  In the example shown in FIG. 17, in addition to the second embodiment, the movable element 102 is provided with an inner surface 620 for transmitting force to and from the valve body 114, and the movable element 102 is configured with an inclined surface 621. That is, the inner surface 620 constitutes the bottom surface of the recess formed on the surface 102 b of the mover 102 facing the magnetic core 107. The inclined surface 621 is formed as a surface connecting the intermediate surface 620 and the opposing surface 102b. By providing the inclined surface 621, the area of the end surface on the magnetic core 107 side of the mover 102 is reduced, so that the magnetic flux density on the attraction surface increases and the attraction force can be improved. Further, since the mass of the mover 102 can be reduced by providing the inner surface 620, the acceleration of the mover 102 at the time of opening / closing is increased, and the time required for opening the valve can be shortened. Further, the contact surface between the restricting portion 114 a provided in the valve body 114 and the mover 102 comes below the upper end surface of the mover 102, whereby the fuel passage 202 provided between the magnetic core 107 and the valve body 114. The passage area becomes larger. Accordingly, since the magnetic path cross-sectional area of the magnetic core 107 can be increased, the magnetic attractive force is improved. Further, by increasing the gap between the valve body 114 and the magnetic core 107, the position of the fuel passage hole 203 provided in the mover 102 can be provided on the inner diameter side. It is possible to suppress the reduction by the passage hole 203 and to improve the suction force.

  In this embodiment, the movable element 102 is provided with the inclined surface 621 so that the thickness of the movable element 102 on the inner diameter side at a position away from the coil 105 is reduced. Due to this effect, when the current supply is stopped from the state where the current is supplied to the coil 105, the residual magnetic flux remaining on the inner diameter side of the mover 102 can be reduced, so that the responsiveness when the valve is closed is improved. Can do.

  As described above, when the inner surface 620 is provided, the movable extension 102 may be provided with the sliding extension 810. When the inner surface 620 is provided, the sliding length with the valve body 114 is shortened, but by providing the sliding extension 810, the sliding length is suppressed while suppressing an increase in the mass of the mover 102. Can be secured, and the inclination of the movable element 102 can be suppressed.

  Further, the inner diameter enlarged portion 201 may be provided on the inner diameter side of the surface of the mover 102 facing the end surface on the mover side of the magnetic core 107. Due to this effect, the distance between the inner diameter enlarged portion 201 and the inner surface 620 of the mover 102 is increased, so that the magnetic flux can be efficiently flowed to the attraction surface of the magnetic core 107 and the attraction force can be improved.

101 Nozzle holder 102 Movable element 103 Housing 104 Bobbin 105 Coil 107 Magnetic core 110 Spring 112 Zero spring 113 Rod guide 114 Valve body 114a Restricting part 115 Plunger rod guide 116 Orifice cup 118 Valve seat 119 Injection port 120 Adjuster pin 121 Seal member 123 Fuel Supply port 130 Integrated member 180 Large diameter portion 181 Taper 190 Grooves 201, 205, 550, 801 Inner diameter enlarged portion 202 Fuel passage 203 Fuel passage holes 206, 604 Movable member side end surface 210 Through hole 301 Recessed portion 302 Inclined surface 303 Lower inner diameter surface 605 Inner diameter large diameter portion 606 Inner diameter small diameter portion 701 First taper 702 Second taper 810 Sliding extension 908 Outer diameter small diameter portion 909 Magnetic restrictor

Claims (7)

A valve body that closes the fuel passage by coming into contact with the valve seat and opens the fuel passage by moving away from the valve seat, a mover that performs the on-off valve operation in cooperation with the valve body, and excitation by energizing the coil A fuel injection device comprising: a magnetic core that generates a magnetic force that drives the mover;
The magnetic core has a hole formed in a direction along the valve axis that opens at an end surface facing the mover,
The hole is formed with an inner diameter enlarged portion whose inner diameter is increased toward the end surface,
The movable element is formed with an insertion hole into which the valve body is inserted and a fuel passage hole located on the outer peripheral side of the insertion hole,
The valve body and the mover are configured as separate members so as to be capable of relative displacement,
The valve body has a restricting portion that restricts relative displacement in the valve opening direction of the movable element with respect to the valve body,
The restricting portion is formed by an enlarged diameter portion having a larger diameter than the valve body,
The restricting portion is located in the inner diameter enlarged portion of the hole in a state where the mover and the magnetic core are in contact with each other.
The range of the inner diameter enlarged portion is configured from the end surface on the mover side of the magnetic core to the upstream portion of the restricting portion,
The center of the fuel passage hole is located on the outer peripheral side with respect to the inner diameter portion that is the minimum diameter of the hole, and the fuel passage hole is axially aligned with the inner diameter portion of the end face of the magnetic core in which the inner diameter enlarged portion is formed. In the overlapping position,
The fuel injection device according to claim 1, wherein a center of the fuel passage hole is located on an inner peripheral side of an inner diameter portion of the end face of the magnetic core in which the inner diameter enlarged portion is formed . The fuel injection device according to claim 1,
The mover has a second hole formed in a direction along the valve shaft that opens to an end surface opposite to the end surface facing the magnetic core,
The fuel injection device according to claim 1, wherein the second hole is formed with an inner diameter enlarged portion whose inner diameter increases toward the opposite end face in a range of half or more in the axial direction of the second hole. The fuel injection device according to claim 1,
The mover has a second hole formed in a direction along the valve shaft that opens to an end surface opposite to the end surface facing the magnetic core,
The fuel injection device according to claim 1, wherein the second hole has an inner diameter enlarged toward the opposite end surface to form an inner diameter enlarged portion having a substantially linear taper shape. The fuel injection device according to claim 2, wherein
A fuel injection characterized in that a starting point position in a radial direction of the inner diameter enlarged portion formed in the second hole is located on an outer peripheral side with respect to an inner diameter portion of the end surface of the magnetic core on which the inner diameter enlarged portion is formed. apparatus. The fuel injection device according to claim 1,
The area of the mover side end surface of the magnetic core, the fuel injection device you being less than 10% as compared to the cross-sectional area of the magnetic core of the upstream portion than the large inner diameter portion.   The fuel injection device according to claim 1,
  One or more taper portions having an angle different from that of the inner diameter enlarged portion are provided in the upstream portion and the downstream portion of the inner diameter enlarged portion,
  The fuel injection device, wherein the taper portion closer to the downstream portion is configured to have a larger angle with the valve shaft.   The fuel injection device according to claim 1,
  The fuel injection device according to claim 1, wherein a portion where the inner diameter of the hole formed in the magnetic core is a minimum is formed in a deeper part of the hole than a position of the restricting part.