JP2022102751A - Electromagnetic fuel injection valve - Google Patents

Abstract

To provide an electromagnetic fuel injection valve which includes valve spring force adjusting means having a simple cylindrical shape, enables reduction of manufacturing costs, and can prevent deterioration of a fuel pressure.SOLUTION: In an electromagnetic fuel injection valve, a valve body (10) moves in a valve opening direction against a biasing force of a valve spring (26) in conjunction with a fixed core (5) being excited to attract a movable core (15). An adjusting pipe (25) which adjusts the biasing force of the valve spring (26) forms a cylindrical shape and is press-fitted in a circulation passage (9). An orifice member (30) including a contracted hole (30n) is disposed sandwiched between the adjusting pipe (25) and the valve spring (26).SELECTED DRAWING: Figure 2

Description

The present invention relates to an electromagnetic fuel injection valve that injects fuel by moving the valve body in the valve opening direction to open a fuel injection hole as the fixed core is excited to attract the movable core.

In this type of electromagnetic fuel injection valve, a valve spring force adjusting means for adjusting the urging force of the valve spring and a fuel adjusting means for adjusting the flow rate of the fuel are provided in the fuel flow path passing through the valve housing. Those provided are known (see, for example, Patent Document 1).

Special Table 2017-503948 Gazette

In the electromagnetic fuel injection valve disclosed in Patent Document 1, an adjusting element (valve spring force adjusting means) for adjusting the urging force of the valve spring is press-fitted into the peripheral wall of the flow passage. The adjustment element houses a synthetic resin strainer basket (housing) and a throttle element that throttles the flow rate of fuel in a deep-drawn sleeve, and the throttle element of the throttle element accommodates the inside of the fuel injection valve. Pressure pulsation is effectively dampened and noise is reduced.

Further, in Patent Document 1, a disk-shaped diaphragm element (orifice member) having a diaphragm hole in the center is fitted in a region where the diameter on the upstream end side of the sleeve is expanded, and is more than a diaphragm element fitted in the sleeve. A cylindrical strainer basket having an outer diameter different in the axial direction is fitted on the downstream side, and a filter element is inserted in the cylinder of the strainer basket.

As described above, the adjusting element disclosed in Patent Document 1 accommodates the throttle element and the filter element in the sleeve, the shape of the sleeve is complicated, and the press-fitting allowance of the sleeve into the flow path peripheral wall is maintained. A complicated pressing process for crimping the drawing element is required, and the problem is that the manufacturing cost increases.

Further, since the throttle element is fitted in the sleeve, a loss of fuel pressure is likely to occur.

The present invention has been made in view of this point, and an object thereof is an electromagnetic type in which the valve spring force adjusting means has a simple cylindrical shape and can reduce the manufacturing cost and prevent the fuel pressure from decreasing. The point is to provide a fuel injection valve.

In order to achieve the above object, the present invention has a injection hole for injecting fuel and a flow passage for flowing fuel to the injection hole, and the flow passage is provided between the inlet of the flow passage and the injection hole. A valve body that moves along the valve body to open and close the injection hole, a valve spring that urges the valve body in the valve closing direction, an adjusting pipe that adjusts the urging force of the valve spring, and a fuel flow rate throttle. The orifice member having a narrowing hole, a fixed core forming a part of the flow passage, and a movable core which is opposed to the suction surface of the fixed core and can move in parallel with the movement of the valve body. In an electromagnetic fuel injection valve in which the valve body moves in the valve opening direction against the urging force of the valve spring as the fixed core is excited to attract the movable core, the adjusting pipe has a cylindrical shape. The first feature is that the orifice member is press-fitted into the flow passage and is sandwiched between the adjusting pipe and the valve spring.

Further, in addition to the first feature, the present invention is characterized in that the fuel filter is arranged on the upstream side of the adjusting pipe of the flow passage.

Further, in the present invention, in addition to the first or second feature, the valve spring is a coil spring, and the orifice member has a columnar convex portion formed in the center of an end surface in contact with the valve spring. This is the third feature.

According to the first feature of the present invention, the adjusting pipe for adjusting the urging force of the valve spring is a cylindrical pipe having a simple shape, does not require a complicated manufacturing process, and has an orifice member. The installation is only sandwiched between the adjusting pipe and the valve spring, and there is no need to press-fit the orifice member into the fuel flow path, which facilitates the assembly process and reduces manufacturing costs. can.

Further, according to the second feature, since the fuel filter is arranged on the upstream side of the adjusting pipe of the flow passage and the fuel filter is not arranged in the adjusting pipe, the fuel pressure is not lost.

Further, according to the third feature, since the orifice member has a columnar convex portion formed in the center of the end surface in contact with the valve spring, the columnar convex portion of the orifice member is fitted into the coil spring which is the valve spring. Since the center position of the orifice member is determined by this, it is possible to prevent the orifice member from being tilted at the time of assembly and to easily assemble the orifice member properly.

It is a longitudinal side view of the electromagnetic fuel injection valve which concerns on one Embodiment of this invention. It is an enlarged view of the part shown by II in FIG.

Hereinafter, an embodiment according to the present invention will be described with reference to FIGS. 1 and 2.

The valve housing 2 of the electromagnetic fuel injection valve 1 is a hollow valve seat member 3 having a valve seat 3s at the front end and coaxially connected to the rear of the valve seat member 3 via a non-magnetic cylinder 4. It is composed of a fixed core 5 and a fuel inlet cylinder 6 coaxially connected to the rear of the fixed core 5, and a flow passage 9 for passing fuel is formed inside the valve housing 2.

In the electromagnetic fuel injection valve 1, the valve seat member 3 side is referred to as the front and the fuel inlet cylinder 6 side is referred to as the rear.

The valve seat member 3 has a small diameter cylinder portion 3a having a front end wall 3ae, a conical cylinder portion 3b extending rearward of the small diameter cylinder portion 3a by gradually expanding the diameter, and a large diameter extending rearward of the conical cylinder portion 3b. It consists of a cylinder portion 3c. A conical valve seat 3s is formed on the front end wall 3ae of the small-diameter tubular portion 3a, and a fuel injection hole 3j for injecting fuel opened in the center of the valve seat 3s is formed.

In the electromagnetic fuel injection valve 1, the fixed core 5 and the fuel inlet cylinder 6 are configured as an integral cylinder, and the rear side of the integral cylinder forms the fuel inlet cylinder 6. A fuel filter 40 is attached to the inlet of the fuel inlet cylinder 6. In the fuel filter 40, a cylindrical housing portion 41 holding the mesh portion 42 is fitted into the fuel inlet cylinder 6.

The electromagnetic fuel injection valve 1 is mounted on a cylinder head with a fuel injection hole 3j formed in a front end wall 3ae at the front end facing the combustion chamber, and a fuel inlet cylinder 6 on the rear side is connected to a fuel rail (not shown). High pressure fuel is supplied.

The inner diameter of the non-magnetic cylindrical body 4 interposed between the large diameter cylinder portion 3c of the valve seat member 3 and the fixed core 5 is equal to the inner diameter of the large diameter cylinder portion 3c of the valve seat member 3, and the outer diameter is a cylinder. It is equal to the outer diameter of the fixed core 5 in the shape. The non-magnetic cylindrical body 4 is liquid-tightly welded to the large-diameter tubular portion 3c with its inner peripheral surface continuous.

Further, the front end portion of the fixed core 5 is liquid-tightly welded by reducing the outer diameter by the thickness of the cylinder wall of the non-magnetic cylinder 4 and slightly fitting it into the non-magnetic cylinder 4.

A cylindrical first guide bush 21 is firmly fixed to the inner peripheral surface of the front end portion of the small diameter tubular portion 3a of the valve seat member 3 by press fitting.

Further, a fitting recess opened in the front end suction surface 5f is formed on the inner peripheral surface of the hollow fixing core 5, and a cylindrical second guide bush 22 is fixed to the fitting recess by press fitting. 2 The inner peripheral surface of the guide bush 22 is continuous with the inner peripheral surface of the fixed core 5. The second guide bush 22 protrudes slightly forward from the front end suction surface 5f of the fixed core 5.

The valve body 10 is housed in the flow passage 9 in the valve housing 2 from the valve seat member 3 to the fixed core 5. The valve body 10 has a spherical valve portion 10a that is attached to and detached from the valve seat 3s to open and close the fuel injection hole 3j, and a round bar that is integrally coupled to the valve portion 10a and extends to the inside of the second guide bush 22. It is composed of a stem portion 10b.

The spherical valve portion 10a of the valve body 10 is in sliding contact with the inner peripheral surface of the first guide bush 21, and the outer diameter of the round bar-shaped stem portion 10b is formed to be smaller than the diameter of the spherical valve portion 10a. ing. A fuel flow path that becomes a part of the flow passage 9 is formed between the inner peripheral surface of the first guide bush 21 and the stem portion 10b of the valve body 10, and the outer peripheral surface of the spherical valve portion 10a is the first. A plurality of flat surface portions 10ap forming a fuel flow path are formed between the guide bush 21 and the guide bush 21.

Therefore, the first guide bush 21 secures a fuel flow path between the valve body 10 and the valve body 10 while guiding the opening / closing operation of the valve body 10.

The stem portion 10b of the valve body 10 has a sliding member 11 slidably fitted to the inner peripheral surface of the second guide bush 22 and a stopper arranged inside the large-diameter tubular portion 3c of the valve seat member 3. The member 12 is firmly fixed by welding or the like. The second guide bush 22 and the sliding member 11 are made of a non-magnetic or weak magnetic material having a hardness higher than that of the fixed core 5.

The sliding member 11 is composed of a cylindrical shaft portion 11a fitted to the stem portion 10b and a flange portion 11b formed at the rear end of the cylindrical shaft portion 11a, and the outer peripheral surface of the flange portion 11b is a second guide bush. It is in sliding contact with the inner peripheral surface of 22. The outer peripheral surface of the flange portion 11b is partially recessed to form a flat surface 11p, and a fuel flow path is formed between the flange portion 11b and the inner peripheral surface of the second guide bush 22.

The stopper member 12 has a cylindrical shape, and an enlarged diameter portion having an enlarged diameter is formed at the front end and the rear end. The movable core 15 is slidably fitted to the stem portion 10b so that a limited stroke can be moved between the stopper member 12 and the sliding member 11 fixed to the stem portion 10b.

The movable core 15 has a disk shape having a circular hole in the center, and the stem portion 10b of the valve body 10 slidably penetrates the central circular hole so as to face the front end suction surface 5f of the fixed core 5. There is. The movable core 15 is slidably supported by the stem portion 10b, and has a slight gap with the continuous inner peripheral surface of the non-magnetic cylindrical body 4 and the large-diameter tubular portion 3c of the valve seat member 3. Move back and forth.

The movable core 15 is formed with a plurality of through holes 15p through which the fuel on the rear side and the fuel on the front side can flow with each other, and the through holes 15p serve as a fuel flow path and accompany the movement of the movable core 15. The resistance is reduced.

A cylindrical adjusting pipe 25 is press-fitted into the inner peripheral wall of the fuel inlet cylinder 6 and fixed at a required position near the fuel filter 40 provided at the inlet of the fuel inlet cylinder 6. An orifice member 30 and a valve spring 26 are interposed between the adjusting pipe 25 and the sliding member 11 fixed to the vicinity of the rear end of the stem portion 10b of the valve body 10.

The orifice member 30 has a disc-shaped portion 30a having a throttle hole 30n for reducing the flow rate of fuel in the center and a columnar convex portion 30b protruding from the center of the end surface of the disc-shaped portion 30a in contact with the valve spring 26. It is formed integrally. The diaphragm hole 30n is continuously formed in the center of the columnar convex portion 30b.

The outer diameter of the disc-shaped portion 30a of the orifice member 30 is substantially equal to the inner diameter of the fuel inlet cylinder 6, and the end surface (rear end surface) of the disc-shaped portion 30a opposite to the convex portion 30b is hollow of the fuel inlet cylinder 6. It abuts on the open front end surface of the adjusting pipe 25 press-fitted into the portion. A valve spring 26 is provided between the annular front end surface around the convex portion 30b of the disk-shaped portion 30a and the rear end surface of the flange portion 11b of the sliding member 11 fixed to the stem portion 10b of the valve body 10. It will be reduced. The valve spring 26 is a coil spring.

The stem portion 10b of the valve body 10 penetrates the sliding member 11 and has a rear end portion protruding from the flange portion 11b of the sliding member 11. The center position of the front end portion of the valve spring 26 is determined by fitting the protruding rear end portion of the stem portion 10b into the front end portion of the coil spring which is the valve spring 26.

On the other hand, the center position of the orifice member 30 can be determined by fitting the cylindrical convex portion 30b of the orifice member 30 into the rear end portion of the coil spring of the valve spring 26 whose front end portion is center-positioned. It is easy to properly assemble the orifice member by preventing the orifice member 30 from tilting at the time of attachment.

Since the valve spring 26 is contracted and interposed between the orifice member 30 and the sliding member 11 which are in contact with the adjusting pipe 25, the sliding member 11 is integrated with the valve body 10 by the valve spring 26. Being urged forward. Then, the set load of the valve spring 26 is adjusted by the press-fitting depth of the adjusting pipe 25 into the fuel inlet cylinder 6.

Further, an auxiliary spring 27, which is a coil spring, surrounds the cylindrical shaft portion 11a of the sliding member 11 and is shrunk between the front end surface of the flange portion 11b of the sliding member 11 and the movable core 15. The auxiliary spring 27 acts so as to separate the sliding member 11 and the movable core 15 from each other with a set load smaller than that of the valve spring 26.

The coil assembly 50 is fitted on the outer peripheral surface from the fixed core 5 to the rear portion of the large-diameter tubular portion 3c of the valve seat member 3 via the non-magnetic cylinder 4.

The coil assembly 50 includes a bobbin 51 that fits on the outer peripheral surface and a magnetic coil 52 that is wound around the bobbin 51, and the outer periphery of the magnetic coil 52 is covered with a coil housing 55.

A coating layer 56 made of synthetic resin is molded on the outer peripheral surface of the front portion of the fixed core 5 and the fuel inlet cylinder 6 at the rear of the coil assembly 50, and at that time, a part of the coating layer 56 projects laterally. A coupler 57, which is an electrical connection insertion port, is formed. A conductor 53 extending from the terminal 54 held by the coupler 57 is connected to the magnetic coil 52, and the conductor 53 is embedded in the coating layer 56.

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

When the magnetic coil 52 is not energized, as shown in FIGS. 1 and 2, the valve body 10 is pressed forward by the urging force of the valve spring 26 via the sliding member 11 and is seated on the valve seat 3s. The fuel injection hole 3j is closed to close the valve. At this time, the movable core 15 is pressed forward by the urging force of the auxiliary spring 27 and is in contact with the stopper member 12, and keeps a predetermined distance from the fixed core 5.

When the magnetic coil 52 is energized, the magnetic flux generated by the energization passes through the fixed core 5, the coil housing 55, the non-magnetic cylinder 4, and the movable core 15 in sequence, and the movable core 15 is first attracted to the fixed core 5 by the magnetic force to assist the magnetic coil 52. While compressing the spring 27, it abuts on the front end of the sliding member 11, further slides the sliding member 11 backward against the urging force of the valve spring 26, and the movable core 15 is attached to the front end of the second guide bush 22. It collides and stops with a gap between the fixed core 5 and the front end suction surface 5f. During that time, the sliding member 11 that moves rearward is accompanied by the stem portion 10b integrated with the stem portion 10b, so that the valve body 10 separates the valve portion 10a from the valve seat 3s and is in the valve open state.

Even if the movable core 15 collides with the front end of the second guide bush 22 and stops, the valve body 10 overshoots due to its inertia, but the stopper member 12 integrated with the valve body 10 collides with the front end surface of the movable core 15. By doing so, the overshoot stops. Since this overshoot compresses the valve spring 26, it is also suppressed by the repulsive force of the valve spring 26.

When the overshoot is stopped, the valve body 10 is held at a predetermined valve opening position by returning to a position where the sliding member 11 abuts on the movable core 15 at the position where the sliding member 11 is sucked by the repulsive force of the valve spring 26.

In one embodiment of the electromagnetic fuel injection valve according to the present invention described in detail above, the following effects are obtained.

The adjusting pipe 25 for adjusting the urging force of the valve spring 26 is a cylindrical pipe having a simple shape, does not require a complicated manufacturing process, and the orifice member 30 is arranged with the adjusting pipe 25 and the valve. Since it is only sandwiched between the springs 26 and it is not necessary to press-fit the orifice member into the peripheral wall of the flow passage 9, the assembly process is facilitated, so that the manufacturing cost can be reduced.

Since the fuel filter 40 is arranged on the upstream side of the adjusting pipe 25 of the flow passage 9 and the fuel filter 40 is not arranged in the adjusting pipe 25, the fuel pressure is not lost.

Since the orifice member 30 has a columnar convex portion 30b protruding from the center of the end surface in contact with the valve spring 26, the columnar convex portion 30b of the orifice member 30 is fitted into the coil spring which is the valve spring 26. As a result, the center position of the orifice member 30 is determined, so that the orifice member 30 can be prevented from being tilted at the time of assembly, and the orifice member 30 can be easily assembled.

Although the electromagnetic fuel injection valve according to the embodiment of the present invention has been described above, the embodiment of the present invention is not limited to the above embodiment, and is carried out in various embodiments within the scope of the gist of the present invention. It includes what is done.

For example, the electromagnetic fuel injection valve 1 can be configured to inject fuel into the intake system of an internal combustion engine.

Further, the stopper member 12 can be integrally formed with the stem portion 10b of the valve body 10.

Further, a guide hole can be formed in the valve seat member 3 instead of the first guide bush 21 that slidably guides the valve portion 10a of the valve body 10.

1 ... Electromagnetic fuel injection valve, 2 ... Valve housing, 3 ... Valve seat member, 3a ... Small diameter cylinder, 3ae ... Front end wall, 3s ... Valve seat, 3j ... Fuel injection hole, 3b ... Conical cylinder, 3c ... Large Diameter cylinder part, 4 ... non-magnetic cylinder, 5 ... fixed core, 6 ... fuel inlet cylinder, 9 ... flow passage,
10 ... Valve body, 10a ... Valve part, 10b ... Stem part, 11 ... Sliding member, 11a ... Cylindrical shaft part, 11b ... Flange part, 11p ... Flat surface, 12 ... Stopper member, 15 ... Movable core, 15p ... Through hole ,
21 ... 1st guide bush, 22 ... 2nd guide bush, 25 ... adjusting pipe, 26 ... valve spring, 27 ... auxiliary spring,
30 ... Orifice member, 30b ... Convex part, 30n ... Filter hole,
40 ... fuel filter, 41 ... housing part, 42 ... mesh part,
50 ... coil assembly, 51 ... bobbin, 52 ... magnetic coil, 53 ... lead wire, 54 ... terminal, 55 ... coil housing, 56 ... coating layer, 57 ... coupler.

Claims (3)

It has a fuel injection hole (3j) for injecting fuel and a flow passage (9) for circulating fuel to the fuel injection hole (3j).
Between the inlet of the flow passage (9) and the fuel injection hole (3j),
A valve body (10) that moves along the flow passage (9) to open and close the fuel injection hole (3j).
A valve spring (26) that urges the valve body (10) in the valve closing direction, and
The adjusting pipe (25) for adjusting the urging force of the valve spring (26) and
An orifice member (30) provided with a throttle hole (30n) for reducing the flow rate of fuel, and
A fixed core (5) constituting a part of the flow passage (9),
A movable core (15) that is opposed to the suction surface (5f) of the fixed core (5) and can move in parallel with the movement of the valve body (10).
Equipped with
An electromagnetic type in which the valve body (10) moves in the valve opening direction against the urging force of the valve spring (26) as the fixed core (5) is excited to attract the movable core (15). In the fuel injection valve
The adjusting pipe (25) has a cylindrical shape and is press-fitted into the flow passage (9).
The orifice member (30) is an electromagnetic fuel injection valve characterized in that it is sandwiched between the adjusting pipe (25) and the valve spring (26). The electromagnetic fuel injection valve according to claim 1, wherein the fuel filter (40) is arranged on the upstream side of the adjusting pipe (25) of the flow passage (9). The valve spring (26) is a coil spring.
The electromagnetic type according to claim 1 or 2, wherein the orifice member (30) has a columnar convex portion (30b) formed in the center of an end surface in contact with the valve spring (26). Fuel injection valve.

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