JP2016166534A - Fuel injection valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection valve capable of easily improving coaxial accuracy of an upstream-side guide portion and a downstream-side guide portion.SOLUTION: In a fuel injection valve including a valve seat and a valve element, opening and closing a fuel passage in cooperation with each other, and an electromagnetic driving portion 9 for driving the valve element, and provided with a fixed iron core 25, a movable iron core 27a connected with the valve element to drive the valve element in an opening/closing valve direction by magnetic attraction force acting on between the fixed iron core 25 and the movable iron core, and an electromagnetic coil 29 generating magnetic flux in a magnetic passage configured between the fixed iron core 25 and the movable iron core 27a by being energized, in the electromagnetic driving portion 9, the movable iron core 27a is composed of an annular member, a rod portion 27b having the valve element at one end portion, is penetrated through the movable iron core 27a in a central axis direction at the other end portion 27bc, and an outer peripheral face 27bd of the other end portion 27bc of the rod portion 27b is constituted to be slide-contacted with an inner peripheral face 25aa of a hole 25a formed on the fixed iron core 25 in the central axis direction.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a fuel injection valve that injects fuel.

  As a background art in this technical field, a fuel injection valve described in JP 2000-8990 A (Patent Document 1) is known. In this fuel injection valve, one magnetic pipe made of a composite magnetic material is magnetized, and only the middle part thereof is made non-magnetic so that the magnetic pipe part, the non-magnetic pipe part and the magnetic valve housing part are integrated. Form. Further, a slidable contact ring slidably contacting the inner peripheral surface of the nonmagnetic pipe portion is formed on the outer peripheral surface of the movable iron core by cutting. By this sliding contact ring, a substantially uniform air gap is formed between the outer peripheral surface of the movable iron core and the inner peripheral surface of the valve housing portion. And when peeling off the movable iron core that is adsorbed to the fixed iron core, the magnetic flux between the movable iron core and the valve housing is improved to improve the responsiveness of the needle valve when the valve is closed, and the movable iron core is movable. The lateral electromagnetic force acting on the iron core can be reduced. Moreover, workability can be improved by forming a slidable contact ring on the outer peripheral surface of the movable iron core (see summary).

  In the fuel injection valve of Patent Document 1, a valve seat slidably supports a lower large-diameter portion formed at a tip portion (an end portion opposite to the movable iron core side) of the valve needle (see paragraph 0019). ), The needle valve is guided in the operation in the direction of the central axis at two points, a sliding contact ring formed on the outer peripheral surface of the movable iron core and the lower large diameter portion. The movable iron core is formed in a hollow shape, and is fixed to the upper end portion of the needle valve by press fitting or the like (see paragraph 0020).

JP 2000-8990 A

  In the fuel injection valve of Patent Document 1, the sliding contact ring is located on the upstream side in the fuel flow direction, and the lower large diameter portion is located on the downstream side. For this reason, the guide portion constituted by the sliding contact ring and the guide surface that guides the sliding contact ring is called the upstream guide portion, and the guide portion constituted by the lower large diameter portion and the guide surface that guides the lower large diameter portion. The description will be made by calling the downstream guide portion.

  In the fuel injection valve of Patent Document 1, in order to achieve coaxial accuracy between the upstream guide portion and the downstream guide portion, it is necessary to finish the outer peripheral surface of the sliding contact ring formed on the movable iron core. Since the movable iron core is fixed to the upper end portion of the needle valve by press-fitting or the like, high-precision finishing is required to improve the coaxial accuracy. In particular, when finishing is performed after the movable iron core is assembled to the needle valve, the manufacturing cost increases.

  An object of the present invention is to provide a fuel injection valve that can easily achieve coaxial accuracy between an upstream guide portion and a downstream guide portion.

In order to achieve the above object, a fuel injection valve according to the present invention includes a valve seat and a valve body that open and close a fuel passage in cooperation with each other, and an electromagnetic drive unit that drives the valve body. A fixed iron core, a movable iron core that is connected to the valve body and acts between the fixed iron core to drive the valve body in the on-off valve direction, and the energized current to the fixed iron core and the movable iron core. In a fuel injection valve having an electromagnetic coil for generating a magnetic flux in a magnetic path formed between an iron core and
The movable iron core is formed of an annular member, and the other end of the rod part having the valve body at one end is provided so as to penetrate the movable iron core in the central axis direction, and the outer peripheral surface of the other end of the rod part Is configured to slidably contact the inner peripheral surface of a hole formed in the central axis direction of the fixed iron core.

  According to the present invention, since the two sliding contact portions that are in sliding contact with the upstream guide surface and the downstream guide surface are configured on the rod portion, the coaxial accuracy between the upstream guide portion and the downstream guide portion can be easily achieved. Can be put out.

  Other effects according to the present invention will be described in the description of the embodiments.

It is a longitudinal cross-sectional view which shows the longitudinal cross-section in alignment with a valve shaft center (center axis line) about one Example of the fuel injection valve which concerns on this invention. It is sectional drawing which expands and shows the vicinity of the nozzle part 8 shown in FIG. FIG. 3 is an enlarged vertical cross-sectional view showing a portion III (around movable iron core 27a) shown in FIG. It is sectional drawing of the internal combustion engine by which a fuel injection valve is mounted.

  An embodiment according to the present invention will be described with reference to FIGS.

  With reference to FIG. 1, the whole structure of the fuel injection valve 1 is demonstrated. FIG. 1 is a longitudinal sectional view showing a longitudinal section along a valve axis (center axis) in an embodiment of a fuel injection valve according to the present invention. The central axis 1a coincides with the axis (valve axis) of the movable element 27 in which the valve element 27c, the rod part (connecting part) 27b and the movable iron core 27a are integrally provided, and the central axis of the cylindrical body 5 It matches.

  In FIG. 1, the upper end portion (upper end side) of the fuel injection valve 1 may be referred to as a base end portion (base end side), and the lower end portion (lower end side) may be referred to as a distal end portion (front end side). The designations of the base end (base end side) and the tip end (tip side) are based on the fuel flow direction or the structure of the fuel injection valve 1 attached to the fuel pipe. Further, the vertical relationship described in this specification is based on FIG. 1 and is not related to the vertical direction in the form in which the fuel injection valve 1 is mounted on the internal combustion engine.

  The fuel injection valve 1 is constituted by a cylindrical body 5 made of a metal material so that the fuel flow path 3 is substantially along the central axis 1a. The cylindrical body 5 is formed in a stepped shape in the direction along the central axis 1a by press working such as deep drawing using a metal material such as magnetic stainless steel. Thereby, as for the cylindrical body 5, the diameter of the one end side 5a is large with respect to the diameter of the other end side 5b.

  A fuel supply port 2 is provided at the proximal end of the cylindrical body 5, and a fuel filter 13 for removing foreign matters mixed in the fuel is attached to the fuel supply port 2.

  The base end portion of the cylindrical body 5 is formed with a flange portion (expanded diameter portion) 5d that is bent so as to expand toward the radially outer side, and the flange portion 5d and the base end side end portion 47a of the cover 47 are formed. An O-ring 11 is disposed in the formed annular recess (annular groove) 4.

  A valve portion 7 including a valve body 27 c and a valve seat member 15 is configured at the distal end portion of the cylindrical body 5. The valve seat member 15 is inserted on the inner side of the distal end side of the cylindrical body 5 and is fixed to the cylindrical body 5 by laser welding 19. The laser welding 19 is performed from the outer peripheral side of the cylindrical body 5 over the entire periphery. In this case, the valve seat member 15 may be fixed to the tubular body 5 by laser welding after the valve seat member 15 is press-fitted inside the distal end side of the tubular body 5.

  A drive unit 9 for driving the valve body 27c is disposed at an intermediate portion of the cylindrical body 5. The drive unit 9 is composed of an electromagnetic actuator (electromagnetic drive unit). Specifically, the drive unit 9 is disposed on the front end side with respect to the fixed iron core 25 inside the cylindrical body 5 and the fixed iron core 25 fixed inside (inner peripheral side) of the cylindrical body 5. The outer periphery of the cylindrical body 5 at a position where the mover (movable member) 27 movable in the direction along the axis 1a, and the fixed iron core 25 and the moveable iron core 27a formed on the mover 27 face each other through the minute gap δ1. The electromagnetic coil 29 is extrapolated to the side, and a yoke 33 that covers the electromagnetic coil 29 on the outer peripheral side of the electromagnetic coil 29.

  A movable element 27 is accommodated inside the cylindrical body 5, and the cylindrical body 5 constitutes a housing surrounding the movable iron core 27 a so as to face the outer peripheral surface of the movable iron core 27 a.

  The movable iron core 27a, the fixed iron core 25, and the yoke 33 constitute a closed magnetic path through which magnetic flux generated by energizing the electromagnetic coil 29 flows. The magnetic flux passes through the minute gap δ1, but in order to reduce the leakage magnetic flux flowing through the cylindrical body 5 at the portion of the minute gap δ1, the non-magnetic portion or the cylindrical body is located at a position corresponding to the minute gap δ1 of the cylindrical body 5. 5 is provided with a weak magnetic portion 5c that is weaker than other portions. Hereinafter, the nonmagnetic portion or the weak magnetic portion 5c will be described simply as the nonmagnetic portion 5c. The nonmagnetic portion 5 c can be formed by performing a demagnetization process on the cylindrical body 5 having magnetism with respect to the cylindrical body 5. Such demagnetization treatment can be performed by, for example, heat treatment. Alternatively, by forming an annular recess on the outer peripheral surface of the cylindrical body 5, the portion corresponding to the non-magnetic portion 5c can be made thinner.

  The electromagnetic coil 29 is wound around a bobbin 31 formed in a cylindrical shape with a resin material, and is extrapolated to the outer peripheral side of the cylindrical body 5. The electromagnetic coil 29 is electrically connected to a terminal 43 provided on the connector 41. An external drive circuit (not shown) is connected to the connector 41, and a drive current is passed through the electromagnetic coil 29 via the terminal 43.

  The fixed iron core 25 is made of a magnetic metal material. The fixed iron core 25 is formed in a cylindrical shape, and has a through hole 25a that penetrates the central portion in a direction along the central axis 1a. The fixed iron core 25 is press-fitted and fixed to the proximal end side of the small-diameter portion 5 b of the cylindrical body 5, and is positioned at the intermediate portion of the cylindrical body 5. Since the large diameter portion 5a is provided on the base end side of the small diameter portion 5b, the fixed iron core 25 can be easily assembled. The fixed iron core 25 may be fixed to the cylindrical body 5 by welding, or may be fixed to the cylindrical body 5 by using welding and press fitting together.

  The mover 27 includes a movable iron core 27a, a rod portion (connection portion) 27b, and a valve body 27c. The movable iron core 27a is an annular member. The valve body 27c is a member that contacts the valve seat 15b (see FIG. 2). The valve seat 15b and the valve body 27c cooperate to open and close the fuel passage. The rod portion 27b has a long and narrow cylindrical shape, and is a member that connects the movable iron core 27a and the valve body 27c. The movable iron core 27a is a member that is connected to the valve body 27c and drives the valve body 27 in the direction of the opening / closing valve by a magnetic attraction acting between the fixed iron core 25 and the movable iron core 27a.

  In the present embodiment, the rod portion 27b and the valve body 27c are configured as separate members, and the valve body 27c is fixed to the rod portion 27b. The rod part 27b and the valve body 27c are fixed by press-fitting or welding. The rod part 27b and the valve body 27c may be integrated by a single member.

  The rod portion 27b has a cylindrical shape, and has a hole 27ba that opens at the upper end of the rod portion 27b and extends in the axial direction. Opening portions 27bf and 27bg are formed on the side surface of the rod portion 27b. A back pressure chamber 37 is formed between the outer peripheral surface of the rod portion 27 b and the inner peripheral surface of the cylindrical body 5. The upper end portion 27bc of the rod portion 27b is inserted into the through hole 25a of the fixed iron core 25, and the fuel passage 3 in the through hole 25a communicates with the back pressure chamber 37 through the hole 27ba and the openings 27bf and 27bg. The hole 27ba and the openings 27bf and 27bg constitute a fuel flow path 3 that connects the fuel passage 3 in the through hole 25a and the back pressure chamber 37.

  A coil spring 39 is provided in the through hole 25 a of the fixed iron core 25. One end of the coil spring is in contact with the upper end portion 27bc of the rod portion 27b. The other end of the coil spring 39 is in contact with an adjuster (adjuster) 35 disposed inside the through hole 25 a of the fixed iron core 25. The coil spring 39 is disposed in a compressed state between the upper end surface (base end side end surface) of the rod portion 27 b and the lower end (end end side end surface) of the adjuster (adjustment member) 35.

  The coil spring 39 functions as a biasing member that biases the mover 27 in a direction (valve closing direction) in which the valve element 27c abuts on the valve seat 15b (see FIG. 2). By adjusting the position of the adjuster 35 in the direction along the central axis 1a in the through hole 25a, the urging force of the movable element 27 (that is, the valve body 27c) by the coil spring 39 is adjusted.

  The adjuster 35 has a fuel flow path 3 that penetrates the central portion in a direction along the central axis 1a. The fuel supplied from the fuel supply port 2 flows through the fuel flow path 3 of the adjuster 35, then flows into the fuel flow path 3 at the tip side portion of the through hole 25 a of the fixed iron core 25, and is configured in the mover 27. It flows to the fuel flow path 3.

  The yoke 33 is made of a metallic material having magnetism, and also serves as a housing for the fuel injection valve 1. The yoke 33 is formed in a stepped cylindrical shape having a large diameter portion 33a and a small diameter portion 33b. The large diameter portion 33a has a cylindrical shape covering the outer periphery of the electromagnetic coil 29, and a small diameter portion 33b having a smaller diameter than the large diameter portion 33a is formed on the distal end side of the large diameter portion 33a. The small diameter portion 33 b is press-fitted or inserted into the outer periphery of the small diameter portion 5 b of the cylindrical body 5. Thereby, the inner peripheral surface of the small diameter portion 33 b is in close contact with the outer peripheral surface of the cylindrical body 5. At this time, at least a part of the inner peripheral surface of the small-diameter portion 33b is opposed to the outer peripheral surface of the movable iron core 27a via the cylindrical body 5, and the magnetic resistance of the magnetic path formed in the opposed portion is reduced. ing.

  An annular recess 33c is formed along the circumferential direction on the outer peripheral surface of the end portion on the front end side of the yoke 33. In the thin part formed in the bottom face of the annular recess 33 c, the yoke 33 and the cylindrical body 5 are joined over the entire circumference by laser welding 24.

  A cylindrical protector 49 having a flange portion 49 a is extrapolated to the distal end portion of the tubular body 5, and the distal end portion of the tubular body 5 is protected by the protector 49. The protector 49 covers the top of the laser welding portion 24 of the yoke 33.

  An annular groove 34 is formed by the flange portion 49a of the protector 49, the small diameter portion 33b of the yoke 33, and the step surface of the large diameter portion 33a and the small diameter portion 33b of the yoke 33, and an O-ring 46 is extrapolated to the annular groove 34. Has been. When the fuel injection valve 1 is attached to the internal combustion engine, the O-ring 46 is liquid-tight and air-tight between the inner peripheral surface of the insertion port formed on the internal combustion engine side and the outer peripheral surface of the small-diameter portion 33b of the yoke 33. Acts as a seal to ensure.

  A resin cover 47 is molded in a range from the middle portion of the fuel injection valve 1 to the vicinity of the proximal end portion. The end portion on the front end side of the resin cover 47 covers a part of the base end side of the large diameter portion 33 a of the yoke 33. Further, the connector 41 is integrally formed of a resin that forms the resin cover 47.

  Next, the configuration of the nozzle unit 8 will be described in detail with reference to FIG. FIG. 2 is an enlarged sectional view showing the vicinity of the nozzle portion 8 shown in FIG.

  The valve seat member 15 is formed with through holes 15d, 15c, 15v, 15e penetrating in the direction along the central axis 1a. A conical surface 15v whose diameter decreases toward the downstream side is formed in the middle of the through hole. A valve seat 15b is formed on the conical surface 15v, and the fuel passage is opened and closed by the valve body 27c coming into and out of contact with the valve seat 15b. The conical surface 15v on which the valve seat 15b is formed may be referred to as a valve seat surface.

  In the through holes 15d, 15c, 15v, and 15e, the hole portions 15d, 15c, and 15v on the upper side from the conical surface 15v constitute a valve body housing hole that houses the valve body 27c. A guide surface 15c for guiding the valve body 27c in the direction along the central axis 1a is formed on the inner peripheral surfaces of the valve body housing holes 15d, 15c, 15v. The guide surface 15 c constitutes a downstream guide surface located on the downstream side of the two guide surfaces for guiding the mover 27.

  The downstream guide surface 15c and the slidable contact surface 27cb of the valve element 27c slidably in contact with the downstream guide surface 15c constitute a downstream guide portion 50A that guides the displacement of the mover 27.

  On the upstream side of the guide surface 15c, a diameter increasing portion 15d that increases in diameter toward the upstream side is formed. The enlarged diameter portion 15d facilitates the assembly of the valve body 27c and serves to enlarge the fuel passage cross section. On the other hand, the lower end portions of the valve body accommodation holes 15d, 15c, and 15v are connected to the fuel introduction hole 15e, and the lower end surface of the fuel introduction hole 15e opens to the distal end surface 15t of the valve seat member 15.

  A nozzle plate 21 n is attached to the distal end surface 15 t of the valve seat member 15. The nozzle plate 21 n is fixed to the valve seat member 15 by laser welding 23. The laser welding part 23 goes around the injection hole forming region so as to surround the injection hole forming region where the fuel injection hole 110 is formed.

  The nozzle plate 21n is formed of a plate-like member (flat plate) having a uniform plate thickness, and a protruding portion 21na is formed at the center portion so as to protrude outward. The protruding portion 21na is formed of a curved surface (for example, a spherical surface). A fuel chamber 21a is formed inside the protruding portion 21na. The fuel chamber 21a communicates with a fuel introduction hole 15e formed in the valve seat member 15, and fuel is supplied to the fuel chamber 21a through the fuel introduction hole 15e.

  A plurality of fuel injection holes 110 are formed in the protruding portion 21na. The form of the fuel injection hole is not particularly limited. A swirl chamber that imparts a swirling force to the fuel may be provided upstream of the fuel injection hole 110. The central axis 110a of the fuel injection hole may be parallel to or inclined with respect to the central axis 1a of the fuel injection valve. Moreover, the structure which does not have the protruding part 21na may be sufficient.

  In this embodiment, the valve portion 7 that opens and closes the fuel injection hole 110 is constituted by a valve seat member 15 and a valve body 27c, and the fuel injection portion 21 that determines the form of fuel spray is constituted by a nozzle plate 21n. And the valve part 7 and the fuel injection part 21 comprise the nozzle part 8 for performing fuel injection. That is, the nozzle portion 8 in the present embodiment is configured by joining the nozzle plate 21n to the tip surface 15t on the main body side (valve seat member 15) of the nozzle portion 8.

  In the present embodiment, the valve element 27c is a ball valve that is spherical. For this reason, a plurality of notch surfaces 27ca are provided at intervals in the circumferential direction at a portion facing the guide surface 15c in the valve element 27c, and a fuel passage is configured by the notch surfaces 27ca. The valve body 27c can be configured by a valve body other than the ball valve. For example, a needle valve may be used.

  With reference to FIG. 3, the structure of the mover 27, particularly the periphery of the movable iron core 27a, will be described in detail. FIG. 3 is an enlarged longitudinal sectional view showing a portion III (around the movable iron core 27a) shown in FIG.

  In the present embodiment, the rod portion 27b is inserted into the inner peripheral 27aa side of the annular movable core 27a, and the movable core 27a is assembled to the outer peripheral surface 27bh of the rod portion 27b. That is, the rod portion 27b and the movable iron core 27a are configured as separate members.

  The upper end portion 27bc of the rod portion 27b penetrates the movable iron core 27a and projects upward from the upper end surface 27ab of the movable iron core 27a. The upper end surface 27ab is a surface facing the lower end surface 25b of the fixed iron core 25. The upper end surface 27ab and the lower end surface 25b constitute a magnetic attraction surface on which a magnetic attraction force acts. A protrusion 27ad is provided on the upper end surface 27ab of the movable iron core 27a to reduce the squeeze force acting between the upper end surface 27ab and the lower end surface 25b of the fixed iron core 25. Therefore, the gap δ1 is the distance between the upper end surface of the protrusion 27ad and the lower end surface 25b of the fixed iron core 25.

  The rod part 27b and the movable iron core 27a are fixed by press-fitting or welding, or press-fitting and welding. The upper end portion 27bc of the rod portion 27b is formed thicker than the lower portion, including the portion where the movable iron core 27a is fixed. In this case, the inner diameter side has a uniform diameter from the lower end to the upper end, and the outer diameter is larger on the upper end than on the lower end. Thereby, the intensity | strength of the site | part to which the movable iron core 27a of the rod part 27b is fixed is raised.

  The upper end portion 27bc of the rod portion 27b is inserted into the through hole 25a of the fixed iron core 25, and the outer peripheral surface 27bd of the upper end portion 27bc is configured to slide with respect to the inner peripheral surface of the through hole 25a. Yes. That is, the inner peripheral surface of the fixed iron core 25 (particularly the inner peripheral surface lower end portion 25aa) constitutes a guide surface for guiding the rod portion 27b. The guide surface 25aa constitutes an upstream guide surface located on the upstream side of the two guide surfaces for guiding the movable element 27. Since the upper end portion 27bc of the rod portion 27b is configured to be thick, even if an eccentric load acts on the mover 27, the mover 27 can be guided firmly.

  The upstream guide surface 25aa and the outer peripheral surface (sliding contact surface or sliding surface) 27bd of the rod portion 27b slidably contacting the upstream guide surface 25aa constitute an upstream guide portion 50B that guides the displacement of the mover 27. .

  The fixed iron core 25 and the movable iron core 27a are made of a magnetic material, whereas the rod portion 27b is made of a nonmagnetic material or a weak magnetic material. Thereby, the rod part 27b does not short-circuit the magnetic path between the fixed iron core 25 and the movable iron core 27a, and a strong magnetic attractive force can be generated between the fixed iron core 25 and the movable iron core 27a. Further, it is possible to prevent the upper end portion 27bc from being attracted to the fixed iron core 25 and becoming inoperable due to the magnetic attractive force acting between the fixed iron core 25 and the upper end portion 27bc of the rod portion 27b.

  As a material of the movable iron core 27a, for example, a ferrite-based or martensitic-based magnetic material, permalloy, or the like can be used. As a material of the fixed iron core 25, for example, a ferrite-based or martensitic-based high-hardness magnetic material or the like can be used. The rod portion 17b can be made of a nonmagnetic or weakly magnetic stainless material, such as SUS304.

  The upper end surface 27be of the rod portion 27b constitutes a spring seat of the coil spring 39. Since the upper end portion 27bc of the rod portion 27b is configured to be thick, a contact area with the coil spring 39 can be ensured.

  In the present embodiment, since the upstream guide surface is configured at the lower end portion 25aa of the inner peripheral surface of the fixed iron core 25, between the outer peripheral surface 27ac of the movable iron core 27a and the inner peripheral surface 5e of the cylindrical body 5, The gap δ2 is configured to exist. That is, even if the mover 27 receives an eccentric load, the eccentric load is received by the lower end portion 25aa of the inner peripheral surface of the fixed core 25 and the upper end portion 27bc of the rod portion 27b, and the outer peripheral surface 27ac of the movable core 27a and the cylindrical body. 5 is configured so as not to contact the inner peripheral surface 5e.

  Since the outer peripheral surface 27ac of the movable iron core 27a and the inner peripheral surface 5e of the cylindrical body 5 are configured in a non-contact manner, it is easy to make the gap δ2 between the outer peripheral surface 27ac and the inner peripheral surface 5e uniform. Become. That is, even when the outer circumferential surface 27ac is guided using the inner circumferential surface 5e as a guide surface, a minute gap δ2 exists between the outer circumferential surface 27ac and the inner circumferential surface 5e. The outer peripheral surface 27ac has a portion in contact with the inner peripheral surface 5e, and is separated from the inner peripheral surface 5e on the opposite side of 180 degrees. Therefore, the gap δ2 between the outer peripheral surface 27ac and the inner peripheral surface 5e cannot be made uniform.

  On the other hand, in the present embodiment, the clearance provided between the outer peripheral surface 27ac of the movable iron core 27a and the inner peripheral surface 5e of the cylindrical body 5 is the outer peripheral surface of the inner peripheral surface lower end portion 25aa of the fixed iron core 25 and the rod portion 27b. It is larger than the clearance δ2 provided between 27bd. For this reason, even if the mover 27 receives an eccentric load and causes misalignment, the ratio to the clearance δ2 provided between the outer peripheral surface 27ac of the movable iron core 27a and the inner peripheral surface 5e of the cylindrical body 5 becomes small. . Thereby, the imbalance of the magnetic attractive force acting on the outer peripheral surface 27ac of the movable iron core 27a can be suppressed, and the eccentric load received by the mover 27 can be suppressed.

  In the present embodiment, since the outer peripheral surface 27ac of the movable iron core 27a and the inner peripheral surface 5e of the cylindrical body 5 are not in contact with each other, finish polishing for the outer peripheral surface 27ac and the inner peripheral surface 5e becomes unnecessary. For example, the movable iron core 27a can be manufactured by forging, and the finishing process for the outer peripheral surface 27ac can be omitted. Thereby, while being able to shorten manufacturing time, manufacturing cost can be suppressed.

  The through hole 25a of the fixed iron core 25 is formed by machining. For this reason, the processing accuracy of the through hole 25a can be easily increased. For this reason, the accuracy required for the upstream guide surface 25aa can be easily obtained. The downstream guide surface 15c needs to finish the lower end portion of the inner peripheral surface of the cylindrical body 5 that fixes the valve seat member 15. However, if the lower end of the inner peripheral surface is finished, the upstream guide surface 25aa and the downstream guide surface 15c can be provided with high accuracy.

  Further, the two portions (sliding contact surfaces with the guide surface) on the movable element 27 side that slide with the upstream guide surface 25aa and the downstream guide surface 15c are both formed in the rod portion 27b. Therefore, on the mover 27 side, if the machining accuracy of the rod portion 27b is managed, the coaxial accuracy of the two parts on the mover 27 side that are in sliding contact with the upstream guide surface 25aa and the downstream guide surface 15c can be machined high. Can do.

  Therefore, according to the present embodiment, the upstream guide portion 50B constituted by the upstream guide surface 25aa and the sliding contact surface 27bd, and the downstream guide portion constituted by the downstream guide surface 15c and the sliding contact portion 17. It becomes easy to obtain the coaxiality (coaxial accuracy) with 50A. Thereby, it becomes easy to maintain the sealing performance between the valve body 27c and the valve seat 15b with high performance.

  When the outer peripheral surface 27ac of the movable iron core 27a is guided by the inner peripheral surface 5e of the cylindrical body 5, in the configuration in which the movable iron core 27a is assembled as a separate member to the rod portion 27b, the rod portion 27b and the outer peripheral surface 27ac of the movable iron core 27a In order to improve the coaxial accuracy, it is necessary to finish the outer peripheral surface 27ac of the movable core 27a after the movable core 27a is assembled to the rod portion 27b. However, when finishing the outer peripheral surface 27ac of the movable iron core 27a after assembling the movable iron core 27a to the rod portion 27b, the manufacturing cost increases.

  In this embodiment, it is not necessary to finish the outer peripheral surface 27ac of the movable iron core 27a after the movable iron core 27a is assembled to the rod portion 27b, and the fuel injection valve 1 can be manufactured at a reduced manufacturing cost.

  Further, in this embodiment, the upstream guide portion 50B is arranged on the upstream side as compared with the case where the upstream guide portion 50B guides the outer peripheral surface 27ac of the movable iron core 27a with the inner peripheral surface 5e of the cylindrical body 5. Can do. For this reason, the distance between the upstream guide portion 50B and the downstream guide portion 50A can be increased, and the inclination of the mover 27 can be suppressed. If the inclination of the mover 27 is increased, the sealing performance between the valve element 27c and the valve seat 15b may be deteriorated. In the present embodiment, since the inclination of the mover 27 can be suppressed, it becomes easy to maintain the sealing performance between the valve element 27c and the valve seat 15b with high performance.

  Further, by reducing the inclination of the mover 27, it is possible to prevent a phenomenon in which one member bites into the other member at the end of the portion that is in sliding contact with each other and the mover 27 is locked to cause malfunction. can do.

  With reference to FIG. 4, an internal combustion engine equipped with a fuel injection valve according to the present invention will be described. FIG. 4 is a cross-sectional view of the internal combustion engine on which the fuel injection valve 1 is mounted.

  A cylinder 102 is formed in the engine block 101 of the internal combustion engine 100, and an intake port 103 and an exhaust port 104 are provided at the top of the cylinder 102. The intake port 103 is provided with an intake valve 105 that opens and closes the intake port 103, and the exhaust port 104 is provided with an exhaust valve 106 that opens and closes the exhaust port 104. An intake pipe 108 is connected to an inlet side end 107 a of an intake passage 107 formed in the engine block 101 and communicating with the intake port 103.

  A fuel pipe 110 is connected to the fuel supply port 2 (see FIG. 1) of the fuel injection valve 1.

  An attachment portion 109 for the fuel injection valve 1 is formed in the intake pipe 108, and an insertion port 109 a for inserting the fuel injection valve 1 is formed in the attachment portion 109. The insertion port 109a penetrates to the inner wall surface (intake passage) of the intake pipe 108, and the fuel injected from the fuel injection valve 1 inserted into the insertion port 109a is injected into the intake passage. In the case of two-way spraying, each fuel spray is injected toward each intake port 103 (intake valve 105) for an internal combustion engine in which two intake ports 103 are provided in the engine block 101.

  The present invention is not limited to the above-described embodiments, and some components can be deleted or other components not described can be added.

  DESCRIPTION OF SYMBOLS 1 ... Fuel injection valve, 1a ... Center axis, 3 ... Fuel passage, 9 ... Drive part, 15c ... Downstream guide surface, 25 ... Fixed iron core, 25a ... Through-hole of fixed iron core 25, 25aa ... Upstream guide surface, 27 ... movable element, 27a ... movable iron core, 27b ... rod part, 27bc ... upper end part (other end part) of rod part 27b, 27bd ... sliding contact surface (outer peripheral surface of rod part 27b) in sliding contact with upstream guide surface 25aa, 27be: upper end surface of rod portion 27b (end surface on the other end side, spring seat surface), 27c: valve body, 27cb: sliding surface of valve body 27c in sliding contact with downstream guide surface 15c, 29: electromagnetic coil, 39 ... Coil spring, 50A ... Downstream guide part, 50B ... Upstream guide part.

Claims (5)

A valve seat and a valve body that cooperate to open and close the fuel passage; and an electromagnetic drive unit that drives the valve body. The electromagnetic drive unit includes a fixed iron core, and the fixed iron core connected to the valve body. A movable iron core that drives the valve element in the direction of the on-off valve by a magnetic attractive force acting between the two, and an electromagnetic that generates a magnetic flux in a magnetic path formed between the fixed iron core and the movable iron core when energized In a fuel injection valve having a coil,
The movable iron core is formed of an annular member, and the other end of the rod part having the valve body at one end is provided so as to penetrate the movable iron core in the central axis direction, and the outer peripheral surface of the other end of the rod part Is a fuel injection valve which is in sliding contact with the inner peripheral surface of a hole formed in the central axis direction in the fixed iron core. The fuel injection valve according to claim 1, wherein
The inner peripheral surface of the hole formed in the fixed iron core and the outer peripheral surface of the other end of the rod portion constitute an upstream guide portion located upstream in the fuel flow direction, and in the fuel flow direction. A fuel injection valve characterized by guiding a displacement in a central axis direction of a movable element constituted by the valve body, the rod part, and the movable iron core together with a downstream guide part positioned on the downstream side. The fuel injection valve according to claim 2,
The fuel injection valve, wherein the movable iron core and the fixed iron core are made of a magnetic material, and the rod portion is made of a non-magnetic material or a weak magnetic material. The fuel injection valve according to claim 3,
The rod portion is formed such that an outer diameter on the other end side is larger than an outer diameter on the one end portion side, and the movable iron core is fixed to a portion where the outer diameter is formed larger. Injection valve. The fuel injection valve according to claim 4, wherein
An end face on the other end side of the rod portion constitutes a spring seat of a coil spring that biases the mover in a valve closing direction.

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