JP2021046812A - Fuel injection valve - Google Patents

Abstract

To provide a fuel injection valve capable of fixing a valve seat member to a valve housing without using welding.SOLUTION: A fuel injection valve 1 comprises a valve element 17 and a valve seat 15b, which cooperate to open and close a fuel passage communicating with a fuel injection hole 110, a first housing part 15 in which the valve seat 15b is formed, and a second housing part 33 to which the first housing part 15 is mounted, in which the first housing part 15 and the second housing part 33 are composed of separate members. The first housing part 15 and the second housing part 33 have locking portions 15i, 33c for locking the first housing part 15 to the second housing part 33. A seal member 46 for sealing fuel is arranged outside of the first housing part 15 and the second housing part 33, and a welded portion straddling both the first housing part 15 and the second housing part 46 is eliminated.SELECTED DRAWING: Figure 2

Description

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

As a background technique in this technical field, an electromagnetic fuel injection valve described in Japanese Patent Application Laid-Open No. 2011-202613 (Patent Document 1) is known. The electromagnetic fuel injection valve described in Patent Document 1 includes a cylindrical valve seat member, a magnetic cylindrical body that is fitted to the rear end portion of the valve seat member and welded liquid-tightly, and the magnetic cylindrical body. A non-magnetic cylinder that is abutted against the rear end and welded liquid-tightly, and a cylindrical fixed core that fits the front end to the inner peripheral surface of the non-magnetic cylinder and is welded liquid-tightly. A valve housing composed of a fuel inlet cylinder integrally connected to the rear end of the fixed core with the same material is provided (see paragraph 0024). The valve seat member includes a valve hole that opens on the front end surface thereof, a conical valve seat that connects to the inner end of the valve hole, and a cylindrical guide hole that connects to the large diameter portion of the valve seat. A steel plate injector plate having a plurality of fuel injection holes communicating with the valve holes is liquid-tightly welded to the front end surface of the seat member (see paragraph 0025).

Japanese Unexamined Patent Publication No. 2011-202613

In the electromagnetic fuel injection valve of Patent Document 1 (hereinafter referred to as a fuel injection valve), a valve seat member having a valve seat is fixed to a magnetic cylinder by welding. In such a configuration, the valve seat formed on the valve seat member may be displaced in the axial direction of the fuel injection valve due to thermal expansion and contraction during welding. The displacement of the valve seat changes the stroke of the valve body. Therefore, it is necessary to adjust the stroke of the valve body after fixing the valve seat member to the valve housing, and in this case, the manufacturing process of the fuel injection valve becomes complicated. Alternatively, in order to prevent the position shift of the valve seat member, it is necessary to add a part for preventing the position shift to the valve housing, and in this case, the number of parts of the fuel injection valve and the process of assembling the parts increase.

An object of the present invention is to provide a fuel injection valve capable of fixing a valve seat member to a valve housing without using welding.

In order to achieve the above object, the fuel injection valve of the present invention is
A valve body and a valve seat that cooperate to open and close a fuel passage communicating with a fuel injection hole, a first housing portion in which the valve seat is formed, a second housing portion to which the first housing portion is attached, and a second housing portion. In a fuel injection valve in which the first housing portion and the second housing portion are made of separate members.
The first housing portion and the second housing portion include a locking portion for locking the first housing portion to the second housing portion.
A sealing member for sealing the fuel is provided on the outside of the first housing portion and the second housing portion.
The welded portion that straddles both the first housing portion and the second housing portion is eliminated.

According to the present invention, the valve seat member can be fixed to the valve housing without using welding.

It is sectional drawing which shows the cross section which includes the central axis 1a of the fuel injection valve 1 and is parallel to the central axis 1a about one Example of the fuel injection valve 1 which concerns on this invention. FIG. 5 is an enlarged cross-sectional view showing a tip portion of the fuel injection valve 1 shown in FIG. 1 including a nozzle portion 8. It is an external view which shows the appearance of the tip part including the nozzle part 8 of the fuel injection valve 1 shown in FIG. It is an external view which shows the appearance of the valve seat member fixing part (yoke 33) which fixes a valve seat member 15. FIG. 5 is a perspective view of the valve seat member 15 shown in FIG. 5A as viewed from diagonally below. FIG. 5 is a cross-sectional view showing a cross section of the valve seat member 15 of the fuel injection valve 1 including the central axis 1a and parallel to the central axis 1a. It is a perspective view of the valve seat member 15 shown in FIG. 4A seen from diagonally above. It is sectional drawing which shows the state which the fuel injection valve 1 was assembled with the attachment part 109, and shows the cross section which includes the central axis 1a and is parallel to the central axis 1a. It is sectional drawing which shows the cross-sectional shape of the modification 46' of a seal member 46. It is sectional drawing which shows the cross-sectional shape of the modification 46 ″ of a seal member 46. It is sectional drawing of the internal combustion engine 100 which mounted the fuel injection valve 1.

Examples of the present invention will be described with reference to FIGS. 1 to 9.

The overall configuration of the fuel injection valve 1 will be described with reference to FIGS. 1 and 2. FIG. 1 is a cross-sectional view showing a cross section of an embodiment of the fuel injection valve 1 according to the present invention, including the central axis 1a of the fuel injection valve 1 and parallel to the central axis 1a. FIG. 2 is an enlarged cross-sectional view showing a tip portion of the fuel injection valve 1 shown in FIG. 1 including a nozzle portion 8.

In this embodiment, the central axis 1a coincides with the axis (valve axis) of the mover 27 integrally provided with the valve body 17 described later, and the central axis of the tubular body 5 described later. In the following description, the vertical direction may be specified, but this vertical direction is based on the vertical direction of FIG. 1, and does not specify the vertical direction in the mounted state of the fuel injection valve 1. The upper end of the fuel injection valve 1 is called the base end, and the lower end is called the tip end. The terms base end and tip end are based on the attachment state of the fuel injection valve 1 to the fuel pipe and the fuel flow direction.

The fuel injection valve 1 is provided with a fuel supply port 2 at the base end of a metal tubular body 5, and the fuel flow path 3 is configured inside the tubular body 5 so as to substantially follow the central axis 1a. ing. A fuel filter 13 for removing foreign matter mixed in the fuel is attached to the fuel supply port 2. Further, at the base end portion of the tubular body 5, an O-ring 11 is arranged as a sealing member in the vicinity of the fuel supply port 2.

At the tip of the tubular body 5, a valve portion 7 including a valve body 17 and a valve seat member 15 is configured. The valve seat member 15 is formed with a through hole 15a penetrating in the direction along the central axis 1a. A conical surface whose diameter is reduced toward the downstream side is formed in the middle of the through hole 15a, and a valve seat (seat portion) 15b is formed on the conical surface. The valve body 17 opens and closes the fuel passage by coming into contact with the valve seat 15b. That is, the valve body 17 and the valve seat 15b cooperate with each other to open and close the fuel passage communicating with the injection hole (fuel injection hole) 110. The entire conical surface on which the valve seat 15b is formed may be referred to as a valve seat surface.

The inner peripheral surface 15c above the conical surface of the through hole 15a constitutes a guide surface (guide hole) that guides the valve body 17 in the direction along the central axis 1a. The lower end of the valve body accommodating hole 15a opens in the tip surface 15t of the valve seat member 15, and this opening constitutes the fuel introduction hole (valve hole) 15d.

The valve seat member 15 is locked by a locking portion that is configured together with the yoke 33 described below. The locking structure of the valve seat member 15 will be described in detail later.

In this embodiment, the nozzle portion 8 for determining the fuel spraying form includes the nozzle plate (injector plate) 21. In this embodiment, the nozzle portion 8 is configured by joining the nozzle plate 21 to the tip surface 15t on the main body side (valve seat member 15) of the nozzle portion 8.

Further, in this embodiment, the valve body 17 uses a ball valve having a spherical shape. The valve body 17 is provided with a plurality of notched surfaces 17a at intervals in the circumferential direction at a portion facing the guide surface 15c, and the notched surfaces 17a form a fuel passage. The valve body 17 is not limited to the ball valve, and for example, a needle valve may be used.

A driving unit 9 for driving the valve body 17 is arranged in the middle portion of the tubular body 5. The drive unit 9 is composed of an electromagnetic actuator (electromagnetic drive unit). Specifically, the drive unit 9 is arranged at the tip side with respect to the fixed iron core 25 fixed inside the tubular body 5 (inner peripheral side) and the fixed iron core 25 inside the tubular body 5 and is at the center. The outer circumference of the tubular body 5 at a position where the movable element (movable member) 27 that can move in the direction along the axis 1a and the movable iron core 27a formed by the fixed iron core 25 and the mover 27 face each other via a minute gap δ. It is composed of an electromagnetic coil 29 extrapolated to the side and a yoke 33 that covers the electromagnetic coil 29 on the outer peripheral side of the electromagnetic coil 29.

The movable iron core 27a, the fixed iron core 25, and the yoke 33 form a closed magnetic path through which the magnetic flux generated by energizing the electromagnetic coil 29 flows. The magnetic flux passes through the minute gap δ, but in order to reduce the leakage magnetic flux flowing through the tubular body 5 at the minute gap δ, the non-magnetic part or the tubular body is located at the position corresponding to the minute gap δ of the tubular body 5. A weak magnetic part whose magnetism is weaker than that of the other parts of 5 is provided. In this embodiment, a thin portion 5a having a thin tubular body 5 is provided as a weak magnetic portion.

The electromagnetic coil 29 is wound around a bobbin 31 formed of a resin material in a tubular shape, and is extrapolated to the outer peripheral side of the tubular body 5. The electromagnetic coil 29 is electrically connected to a terminal 43 provided on the connector 41. The coil device 70 is composed of an electromagnetic coil 29, a bobbin 31, a terminal 43, and the like. An external drive circuit (not shown) is connected to the connector 41, and a drive current is applied to 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 tubular shape and has a through hole 25a that penetrates the central portion in the direction along the central axis 1a. The fixed iron core 25 is press-fitted and fixed to the tubular body 5 and is located in the middle portion of the tubular body 5. The fixed iron core 25 may be fixed to the tubular body 5 by welding, or may be fixed to the tubular body 5 by using welding and press-fitting in combination.

The mover 27 has a movable iron core 27a on the base end side. The mover 27 has a small diameter portion (connecting portion) 27b on the tip end side with respect to the movable iron core 27a, and the valve body 17 is fixed to the tip end of the small diameter portion 27b by welding. The valve body 17 forms a part of the mover 27 to form the valve portion 7. In this embodiment, the movable iron core 27a and the connecting portion 27b are integrally formed (one member made of the same material), but the two members may be joined to each other.

As described above, in the present embodiment, the movable iron core 27a is connected to the valve body 17 and drives the valve body 27 in the on-off valve direction by the magnetic attraction force acting between the movable iron core 27 and the fixed iron core 25. Further, the outer peripheral surface of the movable iron core 27a is in sliding contact with the inner peripheral surface of the tubular body 5, so that the mover 27 is guided to move in the direction along the central axis 1a (opening / closing valve direction).

Inside the mover 27, a fuel passage 3 for supplying fuel from the fixed iron core 25 side to the fuel injection hole 110 side is configured.

A coil spring 39 is arranged in a compressed state between the adjuster 35 arranged in the through hole 25a of the fixed iron core 25 and the movable iron core 27a. The coil spring 39 functions as an urging member that urges the mover 27 in the direction in which the valve body 17 abuts on the valve seat 15b (valve closing direction).

The yoke 33 is made of a magnetic metal material and has a cylindrical shape to cover the outer circumference of the electromagnetic coil 29. The yoke 33 is formed as a stepped cylindrical member having a large diameter portion 33a, a small diameter portion 33b, and a stepped surface 33d formed between the large diameter portion 33a and the small diameter portion 33b. The large diameter portion 33a is provided on the upper end side (base end side) of the yoke 33, and the small diameter portion 33b is provided on the lower end side (tip side) of the yoke 33.

The yoke 33 is press-fitted or inserted so that the lower end thereof is in contact with the outer peripheral surface of the tubular body 5. The tip end portion of the yoke 33 is joined to the tubular body 5 over the entire circumference by laser welding 24. The laser welding 24 is performed inside the annular groove 33c provided at the distal end of the yoke 33. Further, the annular groove 33c constitutes a locking portion for locking the valve seat member 15. The locking structure of the valve seat member 15 will be described in detail later.

The tubular body 5, the yoke 33, and the valve seat member 15 form a housing (valve housing) of the fuel injection valve 1 that accommodates the mover 27 and forms a fuel passage inside. In particular, the valve seat member 15 is formed with a valve seat 15b and constitutes a housing portion (first housing portion) for accommodating the valve body 17, and the yoke 33 is an upper portion of the mover 27 and a housing portion (first housing portion) for accommodating the electromagnetic coil 29. 2 Housing part). The first housing portion 15 and the second housing portion 33 are made of separate members, and the first housing portion 15 is attached to the second housing portion 33.

A valve seat member 15 having a flange portion 15f at the upper end portion is assembled to the tip portion of the tubular body 5. The O-ring 46 is extrapolated into the annular groove 45 between the flange portion 15f and the large diameter portion 33a of the yoke 33. The O-ring 46 is inserted as a seal member for ensuring liquidtightness and airtightness between the insertion port 109a formed on the internal combustion engine side and the fuel injection valve 1 when the fuel injection valve 1 is attached to the internal combustion engine. It functions as a buffer material between the mouth 109a and the mouth 109a. That is, in this embodiment, the resin protector provided for holding the O-ring 46 is eliminated, and the metal valve seat member 15 is provided with the function of the resin protector.

The resin cover 47 is molded and covered with the resin cover 47 from the intermediate portion of the fuel injection valve 1 to the vicinity of the base end side end portion. The resin cover 47 covers the wiring member connecting the electromagnetic coil 29 and the terminal 43, and the connector 41 is integrally formed of the resin material forming the resin cover 47.

As shown in FIG. 2, a nozzle plate 21 is attached to the tip end surface 15t of the valve seat member 15. The nozzle plate 21 is fixed to the valve seat member 15 by laser welding 23. The nozzle plate 21 is made of a plate-shaped member (flat plate) having a uniform plate thickness, and a protruding portion 21a is formed in the central portion so as to protrude outward. The projecting portion 21a is formed so as to form a curved surface (for example, a spherical surface), and a fuel chamber is formed inside the projecting portion 21a. The fuel chamber inside the projecting portion 21a communicates with the fuel introduction hole 15d, and fuel is supplied through the fuel introduction hole 15d.

Next, the operation of the fuel injection valve 1 will be described.

When the electromagnetic coil 29 is in a non-energized state and no drive current is flowing through the electromagnetic coil 29, the mover 27 is urged in the valve closing direction by the coil spring 39, and the valve body 17 abuts (seats) the valve seat 15b. It is in a state of being. In this case, there is a gap δ between the distal end surface of the fixed iron core 25 and the proximal end surface of the movable iron core 27a. In this embodiment, this gap δ is equal to the stroke of the mover 27 (that is, the valve body 17).

When the electromagnetic coil 29 is switched to the energized state and a drive current flows through the electromagnetic coil 29, magnetic flux is generated in the closed magnetic path composed of the movable iron core 27a, the fixed iron core 25, and the yoke 33. Due to this magnetic flux, a magnetic attraction force is generated between the fixed iron core 25 and the movable iron core 27a that face each other with the gap δ in between. When this magnetic attraction overcomes the urging force of the coil spring 39 and the resultant force such as the fuel pressure acting on the mover 27 in the valve closing direction, the mover starts to move in the valve opening direction. When the mover 27 moves in the valve opening direction by a distance δ equal to the gap δ and comes into contact with the fixed iron core 25, the movable iron core 27a is stopped from moving in the valve opening direction and is in a stationary state (valve opening stationary state). To reach.

When the mover 27 moves in the valve opening direction and the valve body 17 separates from the valve seat 15b, a gap (fuel flow path) is formed between the valve body 17 and the valve seat 15b, and a protrusion is formed through the fuel introduction hole 15d. Fuel flows into the fuel chamber inside the portion 21a. The fuel supplied to the fuel chamber from the fuel introduction hole 15d flows into the inside of the fuel injection hole 110 through the inlet opening of the fuel injection hole 110, and is injected to the outside of the fuel injection valve 1 from the outlet opening of the fuel injection hole 110. ..

When the energization of the electromagnetic coil 29 is cut off, the magnetic attraction force decreases and eventually disappears. At this stage, when the magnetic attraction force becomes smaller than the urging force of the coil spring 39, the mover 27 starts moving in the valve closing direction. When the valve body 17 comes into contact with the valve seat 15b, the valve body 17 closes the valve portion 7 and reaches a stationary state (valve closed stationary state).

Open from the time when the mover 27 moves in the valve opening direction and the valve body 17 starts to separate from the valve seat 15b to the time when the mover 27 moves in the valve closing direction and the valve body 17 comes into contact with the valve seat 15b again. The valve body 17 is in contact with the valve seat 15b and the valve is closed while the valve body 17 is in contact with the valve seat 15b and is referred to as a valve closed state or a valve closed state.

Hereinafter, the fixed structure of the valve seat member 15 according to this embodiment will be described.

FIG. 3 is an external view showing the appearance of the tip portion of the fuel injection valve 1 shown in FIG. 1 including the nozzle portion 8.

In this embodiment, the distal end of the yoke 33 covers the radial outside of the distal end of the tubular body 5, and the valve seat member 15 covers the radial outer of the distal end of the yoke 33. .. In this case, the valve seat member 15 covers the outer peripheral surface of the small diameter portion 33b of the yoke 33, particularly the portion of the small diameter portion 33b where the annular groove 33c is formed.

The valve seat member 15 has an annular flange portion 15f formed so as to project radially outward from the upper end portion thereof, and is composed of a small diameter portion 33b of the yoke 33, a stepped surface 33d, and a flange portion 15f. An O-ring 46 is extrapolated into the annular groove 45. The stepped surface 33d and the upper end surface (base end side end surface) 15fa of the flange portion 15f form the side surface of the annular groove 45, and the outer peripheral surface of the small diameter portion 33b constitutes the bottom surface of the annular groove 45.

The valve seat member 15 is a member on which the valve seat 15b is formed, and is a metal member. Therefore, in this embodiment, the surface of the tip side portion of the fuel injection valve 1 from the tip end side portion of the large diameter portion 33a of the yoke 33 is made of metal. However, a resin O-ring 46 is externally inserted into the portion of the annular groove 45. The width dimension W45 of the annular groove 45 is slightly larger than the width dimension W46 of the O-ring 46, and the gap dimensions δ1 and δ2 between the O-ring 46 and the side surfaces 15fa and 33d of the annular groove 45 are set to small values. There is. The width dimension W45 of the annular groove 45 is the same as the width dimension W46 of the O-ring 46 or smaller than the width dimension W46 of the O-ring 46 within the range in which the resin O-ring 46 can be fitted into the annular groove 45. May be set to. In this case, the O-ring 46 comes into contact with the side surfaces 15fa and 33d of the annular groove 45, and the gap dimensions δ1 and δ2 become zero.

FIG. 4A is an external view showing the appearance of the valve seat member fixing portion (yoke 33) for fixing the valve seat member 15. FIG. 4B is a perspective view of the valve seat member 15 shown in FIG. 5A as viewed from diagonally below.

The small diameter portion 33b of the yoke 33 is formed with an annular groove 33c that is recessed from the outer peripheral surface to form a concave shape and is formed in an annular shape in the circumferential direction. Axial groove 33c1 and widening groove (circumferential groove) 33c2 are provided as locking portions (locking groove-shaped portion or groove-shaped portion) for locking the valve seat member 15 in a part of the annular groove 33c. The locking groove portion 33c3 is formed. Further, the tip portion of the yoke 33 is provided with a tapered surface 33f whose diameter is reduced toward the tip side.

The axial groove portion 33c1 is formed in a direction along the central axis 1a of the fuel injection valve 1 so as to penetrate from the front end side side surface 33cc of the annular groove 33c to the tip end side end surface 33e of the yoke 33. The length (width) of the axial groove portion 33c1 in the circumferential direction is formed to have the size of the dimension W33c1.

The widening groove portion (circumferential groove portion) 33c2 is formed so as to widen the groove width dimension W33c of the annular groove 33c at a portion of the side surface 33ca on the base end side of the annular groove 33c including a position facing the axial groove portion 33c1. It is a groove portion, which is connected to the axial groove portion 33c1 and extends in the circumferential direction. That is, the groove width dimension W33c2 in the widened groove portion 33c2 is larger than the groove width dimension W33c of the annular groove 33c (W33c2> W33c).

The locking groove portion 33c3 is formed in a part of the widening groove portion (circumferential groove portion) 33c2, and is formed so that the groove width W33c2 of the widening groove portion 33c2 is further widened by the dimension D33c3 on the front end side side surface 33cc of the annular groove 33c. The groove width dimension W33c-2-3 of the locking groove portion 33c3 has a dimension including the widening portion of the widening groove portion 33c2 and the widening portion D33c3 of the locking groove portion 33c3 in the groove width W33c of the annular groove 33c. Therefore, the groove width dimension W33c-2-3 is larger than the groove width dimension W33c of the annular groove 33c and the groove width dimension W33c2 in the widened groove portion 33c2 (W33c-2-3> W33c, W33c-2-3> W33c2). The length (width) of the locking groove portion 33c3 in the circumferential direction is formed to have the size of the dimension L33c3.

The locking groove-shaped portions (groove-shaped portions) 33c1, 33c2, 33c3 are located on the front end side side surface 33cc between the axial groove portion 33c1 and the locking groove portion 33c3, from the groove width dimension W33c-2-3 in the locking groove portion 33c3. The protrusion 33c4 is formed so that the groove width is narrowed. The protrusion 33c4 is formed so as to project toward the center of the annular groove 33c with respect to the side surface of the locking groove 33c3, but in this embodiment, the same surface as the tip side side surface 33cc of the annular groove 33c is formed in the direction of the central axis 1a. It is formed to form.

The widening groove 33c2 is the same as the dimension L33c1-4-3 in the range in which the axial groove 33c1, the protrusion 33c4 and the locking groove 33c3 are provided in the circumferential direction of the small diameter portion 33b of the yoke 33, or the dimension L33c1- in this range. It is provided in the range L33c2 having a size larger than 4-3. That is, the circumferential length dimension L33c2 of the widening groove portion 33c2 is equal to the circumferential length dimension L33c1-4-3 in the range in which the axial groove portion 33c1, the protrusion 33c4 and the locking groove portion 33c3 are provided, or L33c1- It is larger than 4-3 (L33c2 ≧ L33c1-4-3). However, in order to ensure that the valve seat member 15 can be attached to and detached from the yoke 33, the length of the widening groove portion 33c2 and the length of the range in which the axial groove portion 33c1, the protrusion portion 33c4 and the locking groove portion 33c3 are provided are provided. The dimensions L33c1-4-3 may be made equal, and both ends of the widening groove 33c2 in the circumferential direction and both ends of the range in which the axial groove 33c1, the protrusion 33c4 and the locking groove 33c3 are provided may be at the same position. preferable.

In this embodiment, laser welding 24 of the yoke 33 and the tubular body 5 is performed inside the annular groove 33c. By performing laser welding on the bottom surface of the annular groove 33c, the thermal energy for laser welding can be reduced. In this embodiment, the axial groove portion 33c1, the widening groove portion 33c2, the protrusion portion 33c4, and the locking groove portion 33c3 are provided in a part of the annular groove 33c for the laser welding 24. As a result, the number of man-hours for forming the annular groove 33c for the laser welding 24, the axial groove portion 33c1, the widening groove portion 33c2, the protrusion portion 33c4, and the locking groove portion 33c3 is reduced, and the arrangement space is saved. Realize.

When it is not necessary to reduce the processing man-hours and the space for arranging the space, the axial groove 33c1, the widening groove 33c2, the protrusion 33c4 and the locking groove 33c3 are provided separately from the annular groove 33c for the laser welding 24. May be good.

FIG. 5A is a cross-sectional view showing a cross section of the valve seat member 15 of the fuel injection valve 1 including the central axis 1a and parallel to the central axis 1a. FIG. 5B is a perspective view of the valve seat member 15 shown in FIG. 4A as viewed from diagonally above.

The valve seat member 15 has an annular flat surface portion (flange surface) 15 g formed on the upstream side of the guide surface 15c from the opening edge of the through hole 15a toward the outer side in the radial direction. Further, the valve seat member 15 has an inner peripheral surface 15h formed from the outer peripheral edge portion of the annular flat surface portion 15g toward the upstream side in the direction along the central axis 1a. The inner peripheral surface 15h is provided with a plurality of convex portions 15i protruding inward in the radial direction about the central axis 1a. The convex portion 15i constitutes a locking portion on the valve seat member 15 side that locks the valve seat member 15 to the yoke 33.

In this embodiment, the annular groove 33c of the yoke 33 constitutes a locking portion on the yoke 33 side that locks the valve seat member 15 to the yoke 33, and the convex portion 15i of the valve seat member 15 and the yoke 33. The annular groove 33c of the above constitutes a locking portion for locking the valve seat member 15 to the yoke 33. That is, the valve seat member (first housing portion) 15 and the yoke (second housing portion) 33 include a locking portion that locks the first housing portion 15 to the second housing portion 33. The locking portion is formed by a convex portion 15i in the first housing portion 15, and has a groove shape having an axial groove portion 33c1, a widening groove portion (circumferential groove portion) 33c2, and a locking groove portion 33c3 in the second housing portion 33. It is composed of parts. In this embodiment, since this groove-shaped portion (locking groove-shaped portion) is formed as a part of the annular groove 33c, it is also possible that a part of the annular groove 33c is a groove-shaped portion (locking groove-shaped portion). Conceivable.

The plurality of convex portions 15i are arranged so as to have an interval in the circumferential direction about the central axis 1a. In this embodiment, the four convex portions 15i are provided, and the intervals between the four convex portions 15i in the circumferential direction are evenly provided.

The circumferential length (width) dimension W15i of the convex portion 15i is smaller than the circumferential length (width) dimension W33c1 of the axial groove portion 33c1 and the groove width dimension L33c3 of the locking groove portion 33c3. Further, the length dimension L15i of the convex portion 15i in the direction along the central axis 1a has a large groove width dimension W33c of the annular groove 33c and is smaller than the groove width dimension W33c2 of the widened groove portion 33c2.

Therefore, the convex portion 15i can be inserted from the axial groove portion 33c1 into the widening groove portion 33c2, and can move in the circumferential direction in the widening groove portion 33c2. Further, the convex portion 15i is fitted into the locking groove portion 33c3 to restrict the movement in the circumferential direction, and is in the state shown in FIGS. 2 and 3. In the cross section of FIG. 2, the convex portion 15i is fitted into the locking groove portion 33c3 so that the peripheral end surface 33c2a of the widening groove portion 33c2 shown in FIG. 4 can be seen above the convex portion 15i. ..

In FIGS. 2 and 3, the O-ring 46 is fitted in the annular groove 45, and by fitting the O-ring 46 in the annular groove 45, the convex portion 15i is prevented from coming off from the locking groove portion 33c3. However, the O-ring 46 is formed of a resin material so as to be elastically deformable, and when the valve seat member 15 is lifted with a strong force against the yoke 33, the convex portion 15i comes out of the locking groove portion 33c3. However, unless the valve seat member 15 is rotated in the circumferential direction in this state, the valve seat member 15 will not fall out of the yoke 33.

In this embodiment, the attachment structure of the valve seat member 15 which is the first housing portion to the yoke 33 which is the second housing portion is an attachment structure using a metal locking portion (engagement portion).

As described above, the tip of the yoke 33 is provided with a tapered surface 33f whose diameter is reduced toward the tip side, and when the tip of the yoke 33 is inserted inside the inner peripheral surface 15h of the valve seat member 15. To make it easier to insert.

FIG. 6 is a cross-sectional view showing a state in which the fuel injection valve 1 is assembled to the mounting portion 109, showing a cross section including the central axis 1a and parallel to the central axis 1a.

Before assembling the fuel injection valve 1 to the mounting portion 109, as shown in FIG. 2, the O-ring 46 is in contact with the bottom surface (small diameter portion) 33b of the annular groove 45, but the O-ring 46 and the annular groove 45 are in contact with each other. There are gaps of dimensions δ1 and δ2 between the O-ring 46 and the both side surfaces 15fa and 33d of the annular groove 45 in a state where they are not in contact with the both side surfaces 15fa and 33d. Alternatively, the O-ring 46 is in contact with one of the side surfaces 15fa and 33d of the annular groove 45, and there is a gap having dimensions δ1 + δ2 between the O-ring 46 and the other side surface.

When the fuel injection valve 1 is assembled to the mounting portion 109, the O-ring 46 is compressed on the inner peripheral surface of the insertion port 109a so as to form a large contact surface with respect to the bottom surface 33b and both side surfaces 15fa and 33d of the annular groove 45. , Elastically deforms.

In this state, at least between the O-ring 46 and the side surface 15fa of the annular groove 45, and between the O-ring 46 and the bottom surface 33b of the annular groove 45 or the side surface 33d of the annular groove 45, from the inside to the outside of the fuel injection valve 1. A seal is configured to prevent fuel from leaking to. On the other hand, between the O-ring 46 and the side surface 15fa of the annular groove 45, and between the O-ring 46 and the inner peripheral surface of the insertion port 109a, liquidtightness and airtightness are provided between the inside of the intake pipe 108 and the outside air. The sealing part to be secured is configured.

In order to seal the fuel, it is necessary to form a sealing portion between the O-ring 46 and the side surface 15fa of the annular groove 45. On the other hand, between the O-ring 46 and the bottom surface 33b of the annular groove 45, and between the O-ring 46 and the side surface 33d of the annular groove 45, a seal portion may be formed on either one of them.

In this embodiment, the seal member for preventing fuel leakage is composed of an O-ring 46 for ensuring liquidtightness and airtightness between the inside of the intake pipe 108 and the outside air, thereby suppressing an increase in the number of parts. it can.

In this embodiment, in order to bring the O-ring 46 into close contact with the bottom surface 33b and the side surfaces 15fa and 33d of the annular groove 45, as shown in FIG. 3, the protrusion dimension Lp from the annular groove 45 of the O-ring 46 is annular. It is made larger than the gap dimensions δ1 + δ2 between the side surfaces 15fa and 33d of the groove 45 and the O-ring 46.

In this embodiment, the O-ring 46 is compressed on the inner peripheral surface of the insertion port 109a so as to come into contact with both side surfaces 15fa and 33d of the annular groove 45, but the fuel injection valve 1 is inserted into the insertion port. In the state before being inserted into the 109a (the state shown in FIG. 2), the annular groove 45 may be in contact with both side surfaces 15fa and 33d. In this case, in the state after the fuel injection valve 1 is inserted into the insertion port 109a (the state shown in FIG. 6), even if a gap is formed between the O-ring 46 and the bottom surface 33b of the annular groove 45, the O-ring is formed. Fuel can be sealed between the 46 and the side surface 33d of the annular groove 45.

In this embodiment, a seal member (O-ring) 46 for sealing fuel is arranged outside the valve seat member (first housing portion) 15 and the yoke (second housing portion) 33, and the valve seat member 15 and the yoke are provided. The welded portion straddling the 33 is eliminated. That is, instead of sealing the fuel by a welded portion straddling between the valve seat member 15 and the yoke 33, the fuel seal is provided on the outside of the housing of the fuel injection valve 1 composed of the valve seat member 15 and the yoke 33. This is done by the welded O-ring (seal member) 46. In order to ensure this sealing, it is necessary to increase the filling rate of the O-ring 46 into the annular groove 45 to a large value.

FIG. 7 is a cross-sectional view showing the cross-sectional shape of the modified example 46'of the seal member 46.

The seal member 46'of this example has a cross-shaped cross section and has four projecting pieces 46'a, 46'b, 46'c, and 46'd. In the seal member 46', the projecting piece 46'a contacts the side surface 33d of the annular groove 45, the projecting piece 46'b contacts the inner peripheral surface of the insertion port 109a, and the projecting piece 46'c contacts the side surface of the annular groove 45. It is arranged in the annular groove 45 so that it comes into contact with 15fa and the projecting piece 46'd contacts the bottom surface 33b of the annular groove 45.

The seal member 46'of this example also has a seal portion that prevents fuel from leaking from the inside to the outside of the fuel injection valve 1 and a seal portion that ensures liquidtightness and airtightness between the inside of the intake pipe 108 and the outside air. , Can be configured.

FIG. 8 is a cross-sectional view showing the cross-sectional shape of the modified example 46 ″ of the seal member 46.

The seal member 46'' of this example has a flat surface portion on three surfaces 46''a, 46''c, 46''d, and is between the two flat surface portions 46''a, 46''c ( The flat surface portion 46''d facing the surface) is composed of a semi-cylindrical surface (a surface obtained by cutting the cylindrical surface in half) 46''b. In the sealing member 46 ″ of this example, the filling rate of the O-ring 46 ″ into the annular groove 45 can be made large, and the sealing performance can be improved.

An internal combustion engine equipped with a fuel injection valve according to the present invention will be described with reference to FIG. FIG. 9 is a cross-sectional view of an internal combustion engine 100 equipped with a fuel injection valve 1.

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 for opening and closing the intake port 103, and the exhaust port 104 is provided with an exhaust valve 106 for opening and closing the exhaust port 104. The intake pipe 108 is connected to the inlet side end 107a of the intake flow path 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.

A mounting portion 109 of the fuel injection valve 1 is formed in the intake pipe 108, and an insertion port 109a into which the fuel injection valve 1 is inserted is formed in the mounting portion 109. The insertion port 109a penetrates to the inner wall surface (intake flow path) 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 flow path. In the case of two-way spraying, each fuel spray is directed 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.

In this embodiment, by eliminating the welding for fixing the valve seat member (first housing portion) 15 and the yoke (second housing portion) 33, the direction of the central axis 1a of the fuel injection valve 1 due to heat shrinkage during welding is eliminated. The displacement of the first housing portion in the above can be eliminated, and the stroke change of the valve body 17 due to heat shrinkage can be eliminated. This eliminates the need for adding a member to prevent the displacement of the first housing portion due to heat shrinkage and the work of readjusting the stroke, improving the productivity of the fuel injection valve 1 and reducing the manufacturing cost of the fuel injection valve 1. The cost can be reduced. Further, the variation in the injection amount of the fuel injection valve 1 is suppressed.

1 ... Fuel injection valve, 1a ... Central axis of fuel injection valve 1, 3 ... Fuel passage, 15 ... Valve seat member (first housing portion), 15b ... Valve seat, 15h ... Second housing portion 33 into which the second housing portion 33 is inserted. 1 Inner peripheral surface of housing portion 15, 15i ... convex portion (locking portion on the first housing portion 15 side), 17 ... valve body, 25 ... fixed iron core, 27a ... movable iron core, 29 ... electromagnetic coil, 33 ... yoke (Second housing portion), 33c ... annular groove, 33c1 ... axial groove portion, 33c2 ... widening groove portion (circumferential groove portion), 33c3 ... locking groove portion, 33c4 ... protrusion, 46 ... O ring (seal member), 15i , 33c1, 33c2, 33c3 ... Locking portion for locking the first housing portion 15 to the second housing portion 33, 25, 27a, 29, 33 ... Electromagnetic drive unit, 33c1, 33c2, 33c3 ... Groove-shaped portion (second) Locking portion on the housing portion 33 side), 109a ... Insertion port of the fuel injection valve 1 formed on the internal combustion engine side, 110 ... Fuel injection hole.

Claims (6)

A valve body and a valve seat that cooperate to open and close a fuel passage communicating with a fuel injection hole, a first housing portion in which the valve seat is formed, a second housing portion to which the first housing portion is attached, and a second housing portion. In a fuel injection valve in which the first housing portion and the second housing portion are made of separate members.
The first housing portion and the second housing portion include a locking portion for locking the first housing portion to the second housing portion.
A sealing member for sealing the fuel is provided on the outside of the first housing portion and the second housing portion.
A fuel injection valve characterized in that a welded portion straddling both the first housing portion and the second housing portion is eliminated. In the fuel injection valve according to claim 1,
The first housing portion includes an inner peripheral surface into which the second housing portion is inserted.
The locking portion on the side of the first housing portion is composed of a convex portion protruding inward in the radial direction from the inner peripheral surface of the first housing portion.
A fuel injection valve characterized in that the locking portion on the side of the second housing portion is formed of a groove-shaped portion into which the convex portion is fitted. In the fuel injection valve according to claim 2,
The groove-shaped portion is formed on an axial groove portion formed in a direction along the central axis of the fuel injection valve, a circumferential groove portion connected to the axial groove portion and formed in the circumferential direction, and a part of the circumferential groove portion. A fuel injection valve characterized by having a locking groove portion formed therein. In the fuel injection valve according to claim 3,
The groove-shaped portion is formed between the axial groove portion and the locking groove portion in the circumferential direction, and has a protrusion that protrudes toward the center of the groove-shaped portion with respect to the side surface of the locking groove portion. Fuel injection valve. In the fuel injection valve according to claim 4,
It is provided with an electromagnetic drive unit that drives the valve body.
The electromagnetic drive unit includes an electromagnetic coil extrapolated in a tubular body and a yoke that covers the electromagnetic coil on the outer peripheral side of the electromagnetic coil.
The second housing portion is composed of the yoke and is provided with an annular groove in the circumferential direction to be welded and joined to the tubular body.
The fuel injection valve is characterized in that the groove-shaped portion is formed as a part of the annular groove. In the fuel injection valve according to claim 5,
The seal member is a fuel injection valve characterized by being an O-ring for ensuring liquidtightness and airtightness between an insertion port of the fuel injection valve formed on the internal combustion engine side and the fuel injection valve.

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