JP2021055616A - Electromagnetic fuel injection valve - Google Patents

Abstract

To provide an electromagnetic fuel injection valve, which includes: a movable core that is fitted on a rod connected to a valve element and is slidable between a valve opening side stopper and a valve closing side stopper; a fixed core having a suction surface facing the movable core; a valve spring urging the valve element in a valve closing direction; and an auxiliary spring that exerts spring force for separating the movable core from the valve opening side stopper to bring the movable core into contact with the valve closing side stopper when a coil is not energized, and which can suppress a bound of the core that is associated with a collision with the valve closing side stopper to stabilize an injection amount, and can cope with highly accurate control.SOLUTION: Recesses T1, T2 working as a fuel reservoir are provided in at least one of an opposed surface of a movable core 41 to a valve closing side stopper 49 and an opposed surface of a valve closing side stopper 49 to a movable core 41. The respective recesses T1, T2 are formed by stepped portions 41s, 49s, which are formed in an inner peripheral surface of the movable core 41 or the valve closing side stopper 49 by recessing the inner peripheral surface one step outward in the radial direction from the inner peripheral surface, and by an outer peripheral surface of a rod 43.SELECTED DRAWING: Figure 2

Description

The present invention comprises an electromagnetic fuel injection valve, particularly a valve housing having a valve seat at one end, a hollow fixed core connected to the other end of the valve housing, and a coil arranged on the outer periphery of the fixed core. A valve body in which a rod is continuously provided in a valve portion that cooperates with a valve seat, a movable core that faces the suction surface of the fixed core and is slidably fitted to the rod, and a coil that is fixed to the rod and is slidably fitted. A valve opening side stopper that abuts on the movable core that is sucked into the suction surface when energized to open the valve body, a valve closing side stopper that is fixed to the rod on the valve seat side of the valve opening side stopper, and a valve body. Electromagnetic fuel injection including a valve spring that urges the coil in the valve closing direction and an auxiliary spring that exerts a spring force that separates the movable core from the valve opening side stopper and brings it into contact with the valve closing side stopper when the coil is not energized. Regarding the valve.

Such an electromagnetic fuel injection valve is already known in Patent Document 1.

Special Table 2002-506502

In such an electromagnetic fuel injection valve, when the valve is opened, only the movable core first slides on the rod of the valve body and is attracted to the fixed core side, accelerates, and then the valve opening side stopper fixed to the rod is released. By pushing up the movable core against the set load of the valve spring, the valve body can be opened quickly, and the valve opening response of the valve body can be improved. When the valve is closed, the movable core urged by the auxiliary spring comes into contact with the valve closing side stopper, thereby minimizing the amount of rebounding of the valve body to the rear due to the seating impact when the valve body is first seated on the valve seat. It is possible to limit it.

By the way, in recent years, it has been required to control the opening and closing of the fuel injection valve with higher accuracy in order to improve the combustion efficiency of the internal combustion engine. It is desirable to prevent the movable core that slides between the stoppers from bouncing due to the reaction caused by the contact with each stopper and causing unstable operation.

In particular, the bounce of the movable core due to contact (collision) with the valve closing side stopper greatly affects the next valve opening operation of the valve body, for example, there is a period during which fuel cannot be injected normally at the time when it should be injected. It may cause problems such as occurrence.

Then, this problem becomes remarkable when the control for narrowing the fuel injection interval is performed, and the injection amount becomes more unstable, so that there is a possibility that the fuel injection valve cannot be controlled with high accuracy.

The present invention has been made in view of such circumstances, and it is possible to suppress the bouncing of the movable core due to contact with the valve closing side stopper to stabilize the injection amount, and it is easy to perform highly accurate control. It is an object of the present invention to provide a compatible electromagnetic fuel injection valve.

In order to achieve the above object, the present invention is disposed of a valve housing having a valve seat at one end, a hollow fixed core connected to the other end of the valve housing, and an outer periphery of the fixed core. A coil, a valve body in which a rod is continuously provided in a valve portion that cooperates with the valve seat, a movable core that faces the suction surface of the fixed core and is slidably fitted to the rod, and the above. A valve opening side stopper that is fixed to the rod and abuts on the movable core that is attracted to the suction surface when the coil is energized to open the valve body, and a valve seat side that is closer to the valve opening side stopper than the valve opening side stopper. The valve closing side stopper fixed to the rod, the valve spring that urges the valve body in the valve closing direction, and the valve closing side by separating the movable core from the valve opening side stopper when the coil is de-energized. In an electromagnetic fuel injection valve provided with an auxiliary spring that exerts a spring force that abuts on the stopper, the surface of the movable core facing the valve closing side stopper and the surface of the valve closing side stopper facing the movable core. A recess serving as a fuel reservoir is provided on at least one of the facing surfaces, and the recess is formed on the inner peripheral surface of the movable core or the valve closing side stopper provided with the recess from the inner peripheral surface. The first feature is that it is formed by a step portion formed by recessing one step outward in the radial direction and an outer peripheral surface of the rod facing the step portion.

Further, in the present invention, in addition to the configuration of the first feature, the step portion extends in a direction substantially along the axis of the rod to form the inner side surface of the recess on the outer side in the radial direction. The second feature is that the surface has a second surface formed so as to connect between the inner end of the first surface and the outer peripheral surface of the rod to form the bottom surface of the recess.

According to the first feature of the present invention, a fuel reservoir is formed on at least one of the facing surface of the movable core with the valve closing side stopper and the facing surface of the valve closing side stopper with the movable core. A recess is provided, and the recess is formed by recessing the inner peripheral surface of the movable core or the valve closing side stopper provided with the recess one step outward in the radial direction from the inner peripheral surface, and a rod. Since it is formed on the outer peripheral surface of the wheel and the surface facing the step portion, the collision speed of the movable core with the valve closing side stopper is reduced in the valve closing process due to the damper effect of the fuel existing in the recess, that is, the fuel reservoir. , The amount of bounce of the movable core due to the collision can be reduced. As a result, the operation of the movable core can be stabilized and the valve body can be opened accurately, so that the fuel injection amount is stable, which is advantageous in supporting highly accurate control of the fuel injection valve. Moreover, since one inner surface of the recess is formed on the outer peripheral surface of the rod, the recess can be easily formed by simply denting a step portion on the inner peripheral surface of the movable core or the valve closing side stopper. As a result, simplification of the processing process for forming the recess is achieved, which can contribute to cost reduction.

Further, according to the second feature, the step portion is a first surface extending in a direction substantially along the axis of the rod and forming an inner surface on the outer side in the radial direction of the recess, and the first surface thereof. Since it has a second surface formed so as to connect between the inner end and the outer peripheral surface of the rod and forming the bottom surface of the recess, the recess has an inner portion necessary for the fuel in the recess to exert the damper effect. A space (that is, a fuel reservoir space) can be easily secured.

A vertical sectional view showing a first embodiment of an electromagnetic fuel injection valve for an internal combustion engine according to the present invention. An enlarged cross-sectional view taken along the line 2 of FIG. 1 showing the opened state of the fuel injection valve. FIG. 2 Corresponding sectional view and partially enlarged sectional view showing the closed state of the fuel injection valve. FIG. 2 Corresponding sectional view showing the state immediately before closing of the fuel injection valve.

First, in FIGS. 1 to 3, the cylinder head 5 of the internal combustion engine E is provided with a mounting hole 7 that opens into the combustion chamber 6, and an electromagnetic fuel injection valve 8 capable of injecting fuel toward the combustion chamber 6. Is mounted in the mounting hole 7.

The valve housing 9 of the electromagnetic fuel injection valve 8 includes a hollow cylindrical housing body 10, a valve seat member 11 that is fitted and welded to the inner circumference of one end of the housing body 10, and the other end of the housing body 10. It is composed of a magnetic cylinder 12 in which one end is fitted to the outer periphery and welded to the housing body 10, and a non-magnetic cylinder 13 in which one end is coaxially coupled to the other end of the magnetic cylinder 12. One end of a fixed core 14 having a hollow portion 15 is coaxially coupled to the other end of the non-magnetic cylindrical body 13, and a fuel supply cylinder 16 leading to the hollow portion 15 is attached to the other end of the fixed core 14. It is integrally and coaxially installed.

The magnetic cylindrical body 12 has a flange-shaped yoke portion 12a integrally provided in an axially intermediate portion thereof, and is housed in an annular recess 17 provided in the cylinder head 5 so as to surround the outer end of the mounting hole 7. A cushion material 18 is interposed between the cylinder head 5 and the yoke portion 12a.

A fuel filter 19 is attached to the other end of the fuel supply cylinder 16, that is, an inlet, and the fuel supply cylinder 16 is fitted to the fuel supply cap 21 provided in the fuel distribution pipe 20 via an annular seal member 22. A bracket 23 is locked to the top of the fuel supply cap 21, and the bracket 23 is detachably fastened to the cylinder head 5 by an appropriate fixing means (for example, a bolt) to a column (not shown) erected on the cylinder head 5. Cylinder.

An elastic member 26 made of a leaf spring is interposed between the fuel supply cap 21 and the annular step portion 25 provided in the middle portion of the fuel supply cylinder 16 and facing the fuel supply cap 21 side. Then, the fuel supply cylinder 16, that is, the electromagnetic fuel injection valve 8, is sandwiched between the cylinder head 5 and the elastic member 26 by the elastic force exerted by the elastic member 26.

The valve seat member 11 has an end wall portion 11a at one end and is formed in a bottomed cylindrical shape. The end wall portion 11a is formed with a conical valve seat 27 and the valve seat. A plurality of fuel injection holes 28 that open near the center of 27 are provided. The valve seat member 11 is fitted and welded to one end of the housing body 10 so as to open the fuel injection hole 28 toward the combustion chamber 6. That is, the valve housing 9 is configured to have a valve seat 27 at one end thereof.

The coil assembly 30 is fitted on the outer peripheral surface from the other end of the magnetic cylinder 12 to the fixed core 14. The coil assembly 30 is composed of a bobbin 31 that fits on the outer peripheral surface and a coil 32 that is wound around the bobbin 31, and one end of a coil housing 33 that surrounds the coil assembly 30 is a magnetic cylinder. 12 is coupled to the outer periphery of the yoke portion 12a.

The outer periphery of the other end of the fixed core 14 is covered with a synthetic resin coating layer 34 that is connected to the other end of the coil housing 33 and molded, and the coating layer 34 has terminals 35 connected to the coil 32. The coupler 34a holding the above is integrally formed so as to project toward one side of the electromagnetic fuel injection valve 8.

With reference to FIG. 3, an annular recess 36 is formed on the outer periphery of one end of the fixed core 14, and a non-magnetic cylindrical body is formed in the annular recess 36 so that the outer peripheral surface is connected to the fixed core 14. The other end of 13 is fitted and liquidtightly welded.

A fitting recess 38 that opens to the suction surface 37 at one end is formed on the inner peripheral surface of one end of the fixed core 14, and a cylindrical guide bush 39 forms one end of the fitting recess 38 in the fitting recess 38. It is fixed by press fitting so as to project slightly from the suction surface 37 of the guide bush 39, and the inner peripheral surface of the guide bush 39 is continuous with the inner peripheral surface of the fixed core 14.

A part of the valve body 40 and the movable core 41 are housed in the valve housing 9 from the valve seat member 11 to the non-magnetic cylindrical body 13. The valve body 40 is formed by connecting a rod 43 extending into the guide bush 39 to a valve portion 42 that opens and closes the fuel injection hole 28 in cooperation with the valve seat 27. The valve portion 42 is formed in a spherical shape so as to slide in the valve seat member 11, and the rod 43 is formed to have a smaller diameter than the valve portion 42. An annular fuel flow path 44 is defined between the valve seat member 11 and the rod 43, and a plurality of flat surface portions 45 serving as fuel flow paths are formed on the outer peripheral surface of the valve portion 42 as a fuel flow path between the valve seat member 11 and the rod 43. Will be done. Therefore, the valve seat member 11 allows the passage of fuel while guiding the opening / closing operation of the valve body 40.

A movable core 41 opposed to the suction surface 37 of the fixed core 14 is slidably fitted to the rod 43. Then, the valve opening side stopper 48 that brings the movable core 41 sucked to the suction surface 37 of the fixed core 14 into contact with the suction surface 37 of the fixed core 14 when the coil 32 is energized causes the valve body 40 to open the valve by the contact of the movable core 41. It is fixed to the rod 43. Further, the valve closing side stopper 49 is arranged and fixed to the rod 43 at intervals on the valve seat 27 side of the valve opening side stopper 48 and the movable core 41. Then, the sliding stroke of the movable core 40 between the valve closing side stopper 49 and the valve opening side stopper 48 along the rod 43 is defined in a limited fixed range.

The valve opening side stopper 48 includes a flange portion 48a that is slidably fitted to the inner peripheral surface of the guide bush 39, and a cylindrical shaft portion 48b that projects from the flange portion 48a toward the movable core 41. .. Then, the inner peripheral portion of the flange portion 48a is welded to the rod 43 by the welding bead 50, and at the valve closing position of the valve body 40, a part of the shaft portion 48b projects toward the movable core 41 side from one end surface of the guide bush 39. Arranged like this. On the other hand, an annular groove 51 is formed on the outer periphery of the valve closing side stopper 49, and the valve closing side stopper 49 is fixed to the rod 43 by a welding bead 52 penetrating the groove bottom 51a of the annular groove 51.

The guide bush 39 and the valve opening side stopper 48 are made of a non-magnetic or weak magnetic material having a hardness higher than that of the fixed core 14, for example, martensitic stainless steel, and have substantially the same hardness.

Again, in FIG. 2, a pipe-shaped retainer 53 is fitted and crimped into the hollow portion 15 of the fixed core 14. A valve spring 54 that urges the valve body 40 in the seating direction to the valve seat 27, that is, in the valve closing direction is reduced between the retainer 53 and the flange portion 48a of the valve opening side stopper 48.

Further, an auxiliary spring 55 surrounding the shaft portion 48b of the valve opening side stopper 48 is reduced between the flange portion 48a of the valve opening side stopper 48 and the movable core 41. The auxiliary spring 55 has a set load smaller than the set load of the valve spring 54, and is always urged to the side where the movable core 41 is separated from the valve opening side stopper 48 and brought into contact with the valve closing side stopper 49. Demonstrate the spring force.

The other end of the rod 43 protrudes from the flange portion 48a of the valve opening side stopper 48 and fits into the inner peripheral surface of the movable end portion of the valve spring 54 to play a role of positioning the rod 43. Further, the shaft portion 48b of the valve opening side stopper 48 is fitted to the inner peripheral surface of the auxiliary spring 55 and plays a role of positioning the auxiliary spring 55.

An annular gap 56 is secured between the outer peripheral surface of the movable core 41 and the inner peripheral surfaces of the magnetic cylinder 12 and the non-magnetic cylinder 13. A flat surface portion 57 serving as a fuel flow path is provided at a plurality of locations on the outer periphery of the flange portion 48a of the valve opening side stopper 48, and a plurality of through holes 58 serving as a fuel flow path are provided in the movable core 41.

In such an electromagnetic fuel injection valve 8, when the coil 32 is not energized, the valve body 40 is pushed by the set load of the valve spring 54 to sit on the valve seat 27 and close the fuel injection hole 28. That is, the movable core 41 is in the valve closed state (see FIG. 2), and the movable core 41 is held in contact with the valve closing side stopper 49 by the set load of the auxiliary spring 55, and a predetermined gap is formed between the movable core 41 and the fixed core 14. I'm keeping it.

When the coil 32 is energized in such a valve closed state, the movable core 41 is first attracted to the fixed core 14 by the magnetic force generated thereby, and abuts on the valve opening side stopper 48 while compressing the auxiliary spring 55. That is, since the movable core 41 slides against the set load of the auxiliary spring 55, which is weaker than the valve spring 54 at the time of its initial movement, it slides quickly when it receives a suction force from the fixed core 14, and opens the valve while accelerating. It comes into contact with the side stopper 48.

When the movable core 41 comes into contact with the valve opening side stopper 48, the valve opening side stopper 48 is quickly pressed and moved against the set load of the valve spring 54, and the movable core 41 collides with one end of the guide bush 39 and stops. To do. During that time, since the valve opening side stopper 48 that presses and moves is fixed to the rod 43, the valve portion 42 is separated from the valve seat 27 and is in the valve opening state (see FIG. 3).

When the movable core 41 impactally contacts one end of the guide bush 39, the valve body 40 composed of the valve portion 42 and the rod 43 overshoots due to its inertia, but the valve closing side integrated with the valve body 40. When the stopper 49 collides with the movable core 41, the overshoot is stopped. During that time, the valve opening side stopper 48 is separated from the movable core 41 by the amount of the overshoot of the valve body 40, and the compression deformation of the valve spring 54 is increased. Therefore, the repulsive force of the valve spring 54 also causes the valve body 40. Overshoot is suppressed.

When the overshoot stops, the repulsive force of the valve spring 54 causes the valve opening side stopper 48 to return to a position where it comes into contact with the movable core 41 in contact with the guide bush 39, whereby the valve body 40 opens a predetermined value. It is held in the valve position. At that time, since the set load of the auxiliary spring 55 is set smaller than the set load of the valve spring 54 that urges the valve body 40 in the valve closing direction, the auxiliary spring 55 has the fixed core 14 when the coil 32 is energized. Does not interfere with the suction of the movable core 41 and the contact of the valve opening side stopper 48 with the movable core 41 by the valve spring 54, and does not hinder the valve opening of the valve body 40 to a predetermined position.

As described above, in the valve opening process of the valve body 40, the impact force applied by the movable core 41 to the guide bush 39 is the impact force when only the movable core 41 first collides with the guide bush 39, and then the valve closing side. Since the stopper 49 is divided into the impact force when the stopper 49 collides with the movable core 41, the respective collision energies become relatively small, preventing wear of the contact portion between the guide bush 39 and the movable core 41 and reducing collision noise. It can be kept small. Moreover, when the valve closing side stopper 49 collides with the movable core 41, the valve spring 54 is deformed more than the amount of compression deformation at the time of normal valve opening, so that the valve spring 54 deforms the valve spring 54 with respect to the movable core 41 of the valve closing side stopper 49. Will be absorbed and the impact force will be mitigated.

When the valve body 40 is opened, the fuel pumped from the fuel pump (not shown) to the fuel supply cylinder 34 is inside the pipe-shaped retainer 53, the hollow portion 15 of the fixed core 14, and the flat portion 57 around the valve opening side stopper 48. The fuel is directly injected from the fuel injection hole 28 into the combustion chamber 6 of the internal combustion engine E through the through hole 58 of the movable core 41, the inside of the valve housing 9, and the flat surface portion 45 around the valve portion 42.

Next, when the energization of the coil 32 is cut off, the valve opening side stopper 48 is pushed by the repulsive force of the valve spring 54, so that the valve opening side stopper 48 is accompanied by the movable core 41 and the valve body 40 and the valve seat 27. It moves to the side and the valve portion 42 is seated on the valve seat 27. At this time, the movable core 41 is seated on the valve seat 27 of the valve portion 42 due to the influence of the residual magnetism between the fixed cores 14 and the relatively small set load of the auxiliary spring 55 that lowers the movable core 41 forward. Moves slightly later than.

By the way, when the valve body 40 is first seated on the valve seat 27, it may bounce off due to the seating impact. In that case, the movable core 41 that descends later is fixed to the valve body 40 that bounces off. By contacting the side stopper 49, the amount of rebound of the valve body 40 can be minimized.

When the rebound of the valve body 40 is suppressed, the valve body 40 is held in the valve closed state by the repulsive force of the valve spring 54 to stop the fuel injection, and the movable core 41 has the valve closing side stopper 49 due to the repulsive force of the auxiliary spring 55. It is held in contact with.

As described above, in the valve closing process of the valve body 40, the impact force exerted by the valve body 40 on the valve seat 27 is the impact force when only the valve body 40 is first seated on the valve seat 27, and then the movable core 41. Is divided into the impact force when the valve collides with the valve closing side stopper 49, and the collision energy of each is relatively small. When the valve body 40 is first seated on the valve seat 27, it bounces off due to the seating impact, and then sits on the valve seat 27 again to give an impact. Since the valve closing stroke from the normal valve opening position of the valve body 40 is extremely small, the impact force exerted on the valve seat 27 is extremely small. As a result, wear of the seating portions of the valve portion 42 and the valve seat 27 can be prevented, and the seating noise can be suppressed to be small.

The structure and operation of the fuel injection valve 8 have been described above, but the following characteristic structure is further added to the fuel injection valve 8 in accordance with the present invention. The characteristic structure will be described below with reference to FIG.

An annular first recess T1 is provided on the surface of the movable core 41 facing the valve closing side stopper 49, while the surface of the valve closing side stopper 49 facing the movable core 41 also faces the first recess T1. An annular second recess T2 is provided. The internal spaces of the first and second recesses T1 and T2 are fuel reservoirs for accommodating a certain amount of fuel, and the valve housing 9 is in a state where the movable core 41 is separated from the valve closing side stopper 49. It communicates directly with the fuel passage inside.

Each of the recesses T1 and T2 is an annular shape formed by recessing the inner peripheral surface of the movable core 41 or the valve closing side stopper 49 provided with the recesses T1 and T2 one step outward in the radial direction from the inner peripheral surface. The step portions 41s and 49s are formed by the outer peripheral surfaces of the rod 43 and the facing surfaces 43o1 and 43o2 with the annular step portions 41s and 49s.

Each of the annular step portions 41s and 49s extends in a direction substantially along the axis of the rod 43 and constitutes a radial inner surface of the recesses T1 and T2 on the outer side. Each recess T1 is formed so as to intersect the axis of the rod 43 with 49s1 (substantially orthogonal in this embodiment) and to connect the inner end in the axial direction of the first surface 41s1, 49s1 with the outer peripheral surface of the rod 43. It has second surfaces 41s2 and 49s2 that form the bottom surface of T2.

Next, the operation of the embodiment will be described with reference to FIG.

In the present embodiment, the first and second recesses T1 and T2 face each other on the surface of the movable core 41 facing the valve closing side stopper 49 and the surface of the valve closing side stopper 49 facing the movable core 41. Each of the recesses T1 and T2 is provided and is formed by recessing one step outward in the radial direction from the inner peripheral surface of the movable core 41 or the valve closing side stopper 49 on which the recesses T1 and T2 are provided. It is formed by the step portions 41s and 49s and the outer peripheral surface of the rod 43. As a result, in the valve closing process (for example, the state immediately before valve closing as shown in FIG. 4), the movable core 41 can be decelerated by the damper effect of the fuel existing in the recesses T1 and T2 (that is, the fuel reservoir). As a result, the collision speed of the movable core 41 with the valve closing side stopper 49 can be reduced, and the amount of bounce of the movable core 41 due to the collision can be reduced. Therefore, the operation of the movable core 41 can be stabilized, and the valve body 40 can be opened accurately and accurately at the next valve opening time, so that the fuel injection amount is stabilized. Thus, it is possible to cope with high-precision control of the fuel injection valve 8 without difficulty.

By the way, the reason why the above damper effect can be obtained is considered as follows, for example. That is, in the valve closing process, the movable core 41 slides vigorously toward the valve closing side stopper 49 (thus, the movable core 41 and the valve closing side stopper 49 rapidly approach each other). At that time, due to the influence of the dynamic pressure due to the sliding (rapid approach), the fuel intervening between the bottom surfaces of the recesses T1 and T2 causes a slight flow (turbulent flow) and mutually occurs inside and outside the recesses T1 and T2. It is presumed that they collide and interfere with each other, which exerts a deceleration action on the movable core 41, and as a result, exerts a damper effect to some extent.

On the other hand, if there is no recess that serves as a fuel reservoir on either of the movable core and the facing surface of the valve closing side stopper like the fuel injection valve of Patent Document 1, the damper effect cannot be expected. In the valve closing process, the movable core may vigorously collide with the valve closing side stopper and may bounce significantly due to the reaction. Then, the bounce affects the next valve opening operation of the valve body to some extent, and a period during which fuel cannot be injected normally occurs at the time when the fuel should be injected, or in some cases, the fuel is injected immediately after the valve is closed. There is a possibility that unnecessary secondary injection may occur when it should not be done, but such a problem is solved in the present embodiment by the damper effect of the fuel in the recesses T1 and T2 as described above.

Further, in each of the recesses T1 and T2 of the present embodiment, the inner surface of one side (inner side in the radial direction of the movable core 41) is the outer peripheral surface of the rod 43 (more specifically, the annular step portion 41s, It is formed by facing surfaces 43o1, 43o2) with 49s. Therefore, the annular recesses T1 and T2 can be easily formed in cooperation with the rod 43 by simply recessing the annular steps 41s and 49s on the inner peripheral surfaces of the movable core 41 and the valve closing side stopper 49. It will be possible. As a result, the processing process for forming the annular recesses T1 and T2 can be simplified, and the manufacturing cost can be reduced accordingly.

Further, the annular step portions 41s and 49s of the present embodiment extend in a direction substantially along the axis of the rod 43 and form the inner side surface of each recess T1 and T2 on the outer side in the radial direction. , 49s1 and second surfaces 41s2, 49s2 formed to connect between the inner end of the first surface 41s1, 49s1 and the outer peripheral surface of the rod 43 and forming the bottom surface of each of the recesses T1 and T2. As a result, each of the recesses T1 and T2 can easily secure an internal space (that is, a fuel reservoir space) necessary for exerting the damper effect on the fuel in the recesses T1 and T2.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various design changes are made without departing from the present invention described in the claims. Is possible.

For example, in the above-described embodiment, recesses T1 and T2 serving as fuel reservoirs are provided on both the surface of the movable core 41 facing the valve closing side stopper 49 and the surface of the valve closing side stopper 49 facing the movable core 41, respectively. However, in the present invention, the recesses T1 or T2 that serve as fuel reservoirs may be provided only on the facing surface of any one of the facing surfaces. In this case, the damper effect of the fuel existing in one of the recesses T1 or T2 (that is, the fuel reservoir) also reduces the collision speed of the movable core 41 with the valve closing side stopper 49 to some extent during the valve closing process, resulting in a collision. Since the amount of bounce of the movable core 41 that accompanies it can be reduced, the desired effects of the present invention can be achieved.

Further, in the above embodiment, the first and second recesses T1 and T2 provided on the surface of the movable core 41 facing the valve closing side stopper 49 and the surface of the valve closing side stopper 49 facing the movable core 41 are designated as annular recesses. Therefore, it is shown that the step portions 41s and 49s formed on the inner peripheral surface of the movable core 41 or the valve closing side stopper 49 for providing this are annular step portions, but the recesses T1 and T2 and the step portion 41s are shown. , 49s need not be formed in a ring shape. For example, the recesses T1 and T2 may be composed of one or a plurality of small recesses extending in the circumferential direction of the rod 43, and in that case, the step portions 41s and 49s may also be formed by one or a plurality of small recesses extending in the circumferential direction of the rod 43. It is composed of small steps.

Further, in the above-described embodiment, the second surfaces 41s2, 49s2 constituting the bottom surfaces of the first and second recesses T1 and T2 are formed as planes substantially orthogonal to the axis of the rod 43, but the second surfaces 41s2, 49s2 are shown. May be a curved surface (for example, a curved surface having an arcuate cross section), or may be a tapered surface.

T1, T2 ... First and second recesses as recesses 8 ... Electromagnetic fuel injection valve 9 ... Valve housing 14 ... Fixed core 27 ... Valve seat 32 ... Coil 37.・ ・ Suction surface 40 ・ ・ ・ Valve body 41 ・ ・ ・ Movable core 41s, 49s ・ ・ Circular step portion 41s1, 49s1 as a step portion ・ ・ First surface 41s2, 49s2 of the step portion ・ ・ Second surface of the step portion 42 ... Valve 43 ... Rods 43o1, 43o2 ... The surface of the outer peripheral surface of the rod facing the step 48 ... Valve opening side stopper 49 ... Valve closing side stopper 54 ... Valve spring 55 ... Auxiliary spring

Claims (2)

A valve housing (9) having a valve seat (27) at one end, a hollow fixed core (14) connected to the other end of the valve housing (9), and an outer periphery of the fixed core (14). Suction of the coil (32) to be installed, the valve body (40) formed by connecting the rod (43) to the valve portion (42) that cooperates with the valve seat (27), and the fixed core (14). A movable core (41) facing the surface (37) and slidably fitted to the rod (43), and the suction surface (41) fixed to the rod (43) when the coil (32) is energized. The valve opening side stopper (48) that abuts the movable core (41) sucked by the 37) to open the valve body (40), and the valve seat (48) rather than the valve opening side stopper (48). The valve closing side stopper (49) fixed to the rod (43) on the 27) side, the valve spring (54) for urging the valve body (40) in the valve closing direction, and the non-coil (32). Electromagnetic fuel injection including an auxiliary spring (55) that exerts a spring force that separates the movable core (41) from the valve opening side stopper (48) and brings it into contact with the valve closing side stopper (49) when energized. In the valve
On at least one of the facing surface of the movable core (41) with the valve closing side stopper (49) and the facing surface of the valve closing side stopper (49) with the movable core (41). Is provided with recesses (T1, T2) that serve as fuel reservoirs.
The recesses (T1, T2) are radially outward from the inner peripheral surface on the inner peripheral surface of the movable core (41) or the valve closing side stopper (49) provided with the recesses (T1, T2). It is formed by a step portion (41s, 49s) formed by recessing one step to the side and an outer peripheral surface of the rod (43) facing the step portion (41s, 49s) facing the step portion (43o1, 43o2). An electromagnetic fuel injection valve characterized by this. The step portions (41s, 49s) extend in a direction substantially along the axis of the rod (43) and form a first surface (T1, T2) of the recesses (T1, T2) on the outer side in the radial direction. 41s1,49s1), a first formed to connect between the inner end of the first surface (41s1,49s1) and the outer peripheral surface of the rod (43) to form the bottom surface of the recesses (T1, T2). The electromagnetic fuel injection valve according to claim 1, further comprising two surfaces (41s2, 49s2).

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