JPH10196487A - Injector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve restraint of the bound amount as well as to secure the stable stroke operation of an injector by exhibiting at least one of a self- alignment function and a bound amount restraining function. SOLUTION: In an injector 1, when an electromagnetic coil 10 is electrified, a fixed core 2, a yoke 3 and a movable core 4 form a magnetic circuit, and the movable core 4 is attracted to the fixed core 2 side against force of a return spring 6 to open a valve. A stopper for regulating the movement amount of the valve opening direction of the movable core 4 is either a stopper element 44 on the movable side is formed into a spherical surface and a stopper element 8' on the fixed side for receiving the stopper element on the movable side is formed into a taper surface or, the stopper element 44 on the movable side and the stopper element 8' on the fixed side are formed into the spherical surfaces, or the stopper element 44 on the movable side and the stopper element 8' on the fixed side are formed into the taper surfaces.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injector (fuel injection valve) for supplying injection fuel to an engine.

[0002]

2. Description of the Related Art An injector of this type has a fuel passage upstream of a valve seat, a fixed core and a movable core having a valve element are axially arranged in a yoke, and an electromagnetic coil is provided around the fixed core. Is provided. The movable core receives the spring force of the return spring, and when the electromagnetic coil is not energized, the valve body contacts the valve seat and is in a closed state. When the electromagnetic coil is energized, the fixed core, the yoke, and the movable core form a magnetic circuit. Then, the movable core is attracted to the fixed core side against the force of the return spring, and the valve is opened.

Also, a technique has been proposed in which a swirler is provided upstream of a valve seat to impart a fuel swirling force to fuel passing when the valve is opened to swirl fuel spray to improve atomization of fuel. Have been.

[0004] Among the injectors that have been widely put into practical use are those that are installed in a part of an intake passage, but recently, an injector is directly attached to a cylinder of an engine to directly inject fuel into the cylinder. A DI method (direct injection; in-cylinder injection method) has been developed.

[0005] DI injectors are evaluated as being capable of ensuring efficient combustion, improving output, and purifying exhaust gas without fuel adhering to the intake pipe wall.

In the case of the DI system, with respect to the pressure resistance,
70 kg maximum in the engine cylinder due to the explosion pressure
/ Cm ² , the cylinder pressure far exceeds the return spring pressure of the injection valve, causing the valve to open incorrectly. Recently, however, the fuel pressure has been reduced by improving the high-pressure pump for fuel supply. By increasing the fuel pressure and the force of the return spring, a valve closing force exceeding the explosion pressure can be applied to the fuel injection valve, thereby solving the problem of the valve malfunction.
In addition, as a result of improving the fuel pressure, the required fuel injection amount can be sufficiently supplied even within an extremely limited time such as the intake stroke, and the demand for the above responsiveness can be met.

[0007] In order to overcome the above-mentioned strong valve closing force, the responsiveness is dealt with by increasing the driving power (electromagnetic attraction force) of the electromagnetic coil using a booster circuit.

As a fuel injection valve of a conventional in-cylinder injection system, for example, there is one disclosed in Japanese Patent Application Laid-Open No. 5-33739.

[0009]

In the case of adopting the DI system, in order to use the injector in an increasingly severe environment, and to meet the demand for improved responsiveness, a more stable stroke than ever before has been achieved. Operation must be ensured. In addition, as a result of increasing the electromagnetic attraction force, the collision force when the movable core comes into contact with the stopper during the electromagnetic attraction increases, and without any consideration, the amount of bounce generated by the collision of the movable core with the stopper increases, and the injected fuel increases. May affect the accuracy of weighing.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object thereof is to provide at least one of self-alignment and bound amount suppression functions, and particularly to an injector such as a DI system used under severe conditions. It is an object of the present invention to provide an injector that can guarantee a stable stroke operation and suppress a bounce amount even in the case of (1).

[0011]

In order to achieve the above object, the present invention basically proposes the following means for solving the problems.

According to a first aspect of the present invention, there is provided a fuel passage upstream of a valve seat, wherein a fixed core and a movable core having a valve element are arranged in an axial direction, and at least a part of the fixed core and the movable core is a yoke. When the electromagnetic coil provided around the fixed core is energized, the fixed core, the yoke, and the movable core form a magnetic circuit, and the movable core is attracted to the fixed core side against the force of the return spring. In the injector that opens the valve, the stopper that regulates the amount of movement of the movable core in the valve opening direction has a movable stopper element (a stopper element provided on the movable core) having a spherical surface and a fixed stopper that receives the movable stopper element. The stopper element on the side has a tapered surface, both the movable stopper element and the fixed stopper element have a spherical surface, and both the movable stopper element and the fixed stopper element have a tapered surface. It characterized in that at or misalignment.

When the movable core is magnetically attracted in the valve opening direction by the exciting action of the electromagnetic coil, in the case of the method described above, the stopper is brought into contact with the fixed and movable stopper elements (that is, the tapered surface and the spherical surface). Since the self-centering effect is exhibited, the movable core is aligned in the assembling state by using this centering effect, so that the movable core is assembled in an appropriate state, and as a result, the stroke is stable even during use. The operation is assured, and the centering action also acts on the seating operation of the movable core-side stopper element (movable-side stopper element) with respect to the fixed-side stopper element when the valve is opened. Hold the gap properly.

In this case, if the valve body and the valve seat are set in a similar relationship to the movable-side stopper element and the fixed-side stopper element, the centering action works at both ends of the movable core.

Even when the movable core (movable-side stopper element) collides with the fixed-side stopper element during the valve-opening operation, the collision occurs between the tapered surface and the spherical surface. As compared with the conventional method (a method in which the fixed-side stopper element and the movable-side stopper element collide with each other in a planar shape), the repulsive force is greatly reduced, so that the bound amount of the movable core is suppressed.

In the method described above, the self-centering action of the movable core and the suppression of bounding are similarly performed.

In the method described above, the effect of suppressing the bound of the movable core is mainly achieved.

According to a second aspect of the present invention, there is provided a fuel passage upstream of a valve seat, wherein a fixed core and a movable core having a valve element are arranged in an axial direction, and at least a part of the fixed core and the movable core is a yoke. When the electromagnetic coil provided around the fixed core is energized, the fixed core, the yoke, and the movable core form a magnetic circuit, and the movable core is attracted to the fixed core side against the force of the return spring. In the injector that opens with a valve, the fixed core is formed of a hollow cylinder having a fuel passage therein, and a return spring of the movable core is inserted into one end of the fixed core to adjust a spring force of the return spring. A hollow cylinder spring adjuster is disposed in the fixed core, while a part of the movable core is inserted through the return spring into one end of the fixed core, Wherein the sphere provided on the core portion distal said positioned springs adjust the end are to receive the guide axial movement by the spring adjusting inner wall.

According to the above construction, since the centering function is exerted not only on the valve element and the valve seat but also on the end faces of the spring adjuster and the movable core, both ends of the movable element of the injector (the combination of the valve element and the movable core) are provided. Performs a self-centering action, thereby increasing the assembly accuracy of the valve element and the movable core, and performing a stable stroke operation.

[0020]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing a first embodiment of the injector of the present invention, FIG. 2 is a partial perspective view of a spring adjuster which is a part thereof, and FIG. 3 is a movement of a valve which is a main part of the above embodiment. It is sectional drawing of the stopper part which performs quantity control, and its periphery.

As shown in FIG. 1, the injector 1 includes a fixed core 2, a yoke 3, and a movable core 4 as magnetic circuit elements of an electromagnetic actuator.

The fixed core 2 is an elongated hollow cylindrical body and a flange 2
A, and a lower half of the flange 2A is provided in the yoke 3. The flange 2A is fitted into the upper opening of the yoke 3 in a suitable state, and presses the inner peripheral edge of the upper opening of the yoke 3 to cause plastic flow as indicated by reference numeral 50, thereby plastically connecting the fixed core 2 and the yoke 3. ing. In addition, this connection includes caulking and the like. The terminal 9 of the electromagnetic coil 10 is provided on the flange 2A.

A nozzle body 15 having a valve seat 7 described below is provided below the yoke 3.

A fuel passage 5 is formed inside the fixed core 2 so as to penetrate in the axial direction. A return spring 6 of the movable core 4 is inserted into one end of the fixed core 2 (an end opposite to the fuel inflow side), and the return spring 6 attaches the movable core 4 in a valve closing direction (toward the valve seat 7). Be inspired. A hollow spring adjuster 8 for adjusting the spring force of the return spring 6 is provided inside the fixed core 2.

The electromagnetic coil 10 is covered with a molding resin 11, a part of the fixed core 2 is inserted and fixed at the center thereof, and is housed in a cylindrical yoke 3 together with a part of the fixed core 2. . The mold resin 11 protects the electromagnetic coil 10 and prevents leakage current. Reference numeral 18 denotes a seal ring for preventing fuel from flowing into the coil assembly.

An electric signal for driving is applied to the electromagnetic coil 10 via the terminal 9. The terminal 9 is embedded in a molded resin molded body 20 disposed above the yoke 3.

At the lower part of the yoke 3, a bottomed cylindrical nozzle body 15 is fixed. A valve seat 7 and an orifice (fuel injection hole) 17 are provided at the bottom of the nozzle body 15, and a fuel swirler (hereinafter, referred to as a swirler) 16 is disposed at the bottom of the nozzle body 15, and the swirler 16 is connected to the valve seat 7. Located upstream of.

The swirler 16 is a disc-shaped chip, and a guide hole (center hole) 16A for the ball valve 13 is provided at the center thereof.
A fuel passage groove 16B is formed in the outer periphery and the bottom of the swirler 16 to allow the fuel passage 14 in the nozzle body 15 to communicate with the guide hole 16A. One end of the fuel passage groove 16B opens tangentially to the guide hole 16A, and
The fuel flowing from 6B to the guide hole 16A is swirled.

The movable core 4 is arranged from the yoke 3 to the internal space of the nozzle body 15 so as to coincide with the axis of the fixed core 2, and is capable of performing a stroke operation in the axial direction.

Here, the structure of the movable core 4 and the movable core 4
The stopper structure for restricting the stroke operation of the above will be described in detail.

The movable core 4 has a flange portion at a portion 4A which is a part of a magnetic circuit, and has substantially the same diameter as the fixed core 2.
A portion 4B below the flange portion 4A has a hollow rod shape, and a fuel passage 40 is provided in the rod. A fuel through hole 41 is provided on a side surface of the rod portion 4B.

The upper surface of the flange portion 4A is open, and a step is formed on the inner wall of the flange portion 4A to be a ring receiving portion 42. Through the opening, a guide ring 19 with a rod portion 4C that becomes a part of the movable core 4 is formed. It is connected to the inner periphery of the flange 4A. This connection is performed, for example, by pressurizing the inner peripheral edge of the flange portion 4A as indicated by reference numeral 43 to cause plastic flow.

The guide ring 19 has a bottomed cylindrical shape, and its inner bottom forms a spring receiver for receiving one end of the return spring 6. A part of the guide ring 19 protrudes from the upper surface of the flange portion 4A and is fitted in the inner periphery of the lower end of the fixed core 2 in a suitable state. Then, the movement of the movable core 4 is guided. A fuel through hole 45 is formed in the bottom of the guide ring 19.

The rod portion 4C is erected integrally with the guide ring 19 at the center of the guide ring 19, and a spherical body 44 is provided at the tip (upper end) thereof.

The movable core 4 is, as described above,
A, a rod portion 4B, 4C, and a guide ring 19, a ball valve 13 at one end, and a sphere 44 at the other end.

When the movable core 4 is provided in the injector, the rod 4C and a part of the guide ring 19 are inserted into the inner periphery of the lower end of the fixed core 2. Rod part 4C
In other words, one end of the movable core 4 is introduced to the inner periphery of the lower end of the fixed core 2 through the return spring 6 located between the guide ring 19 and the spring adjuster 8. The sphere 44 at one end of the movable core 4 serves as a movable-side element of a stopper that restricts the movement of the movable core 4 in the valve opening direction. The above sphere 4
The stopper element on the fixed side for receiving the spring 4 is constituted by one end (lower end) 8 'of the spring adjuster 8, and the one end 8' forms a tapered surface as shown in FIGS.

The spring adjuster 8 is provided with a thread groove on a part of its outer periphery, and is screwed to the inner periphery of the fixed core 2 so as to be adjustable in the axial direction. The inner diameter of the lower end side of the fixed core 2 is made larger than the outer diameter of the spring adjuster 8, and an annular passage 46 is secured between the inner and outer diameters. As shown in FIGS. 1 to 3, a fuel through hole 21 for communicating the inside of the adjuster 8 and the above-described annular passage 46 is provided on a lower end wall surface of the spring adjuster 8.

The flange 4A and the rod 4B of the fixed core 2, the yoke 3, and the movable core 4 are made of a magnetic material, and the guide ring 19 with the rod 4C, the sphere 44, the ball valve 13, the sphere 44, and the spring adjuster 8 are provided. Molded with non-magnetic material.

The flange portion 4A is housed in the yoke 3, and the lower rod portion 4B is located in the internal space (fuel passage) 14 of the nozzle body 15, and the ball valve 13 at the tip is used when the electromagnetic coil 10 is not energized. It receives the spring force and fuel pressure of the return spring 6 and contacts the valve seat 7 to keep the valve closed.

When an electric signal is applied to the electromagnetic coil 10 to make it conductive, a magnetic circuit is formed by the fixed core 2, the yoke 3 and the movable core 4, and the movable core 4 is magnetically attracted to the fixed core 2 side. Further, the ball valve 13 moves along with the movable core 4 while being guided by the inner periphery of the swirler 16, moves away from the valve seat 7, and opens.

The amount of movement of the movable core 4 when the valve is opened is such that a sphere (movable-side stopper element) 44 provided at one end of the movable core 4 comes into contact with a stopper (fixed-side stopper element) 8 ′ provided on the spring adjuster 8. Regulated by the ball valve 1
An annular gap having a desired opening area is formed between the valve seat 3 and the valve seat 7, and the valve is opened.

When the valve is in the open state, the fuel flows through the fuel passages 5 and 5 provided in the fixed core 2 through piping devices such as a fuel pump, a fuel pressure regulator, and an accumulator (not shown).
Filter 22, spring adjuster 8 and its through hole 2
1, annular passage 46, inside of lower end of fixed core 2, fuel through hole 45 provided in guide ring 19, internal passage 4 of rod portion 4B
The fuel is injected directly into the cylinder of the engine via the orifice 17 through the fuel passage 41, the passage 14 in the nozzle body 15, and the swirler 16.

The present embodiment has the following effects.

(1) Since the fixed side element 8 'is a tapered surface and the movable side element 44 is a spherical surface, the stopper exerts a self-centering action by contact between the tapered surface and the spherical surface. By performing the alignment of the movable core 4 at the time of assembling using this centering action, the movable core is assembled in an appropriate state. As a result, a stable stroke operation is assured even during use, and the centering action also acts on the seating operation of the movable core 4 on the stopper 8 'when the valve is opened, thereby forming a gap between the ball valve 13 and the valve seat 7. The appropriate annular gap is maintained. In this example, since the ball valve 13 and the valve seat 7 are set in a similar relationship to the movable-side stopper element 44 and the fixed-side stopper element 8 ', the centering action works at both ends of the movable core. Stable stroke operation is guaranteed.

(2) Even when the movable stopper element 44 collides with the fixed stopper element 8 ', the axial repulsion generated by the collision is reduced (the repulsion is composed of the axial component and the perpendicular component). Components which are perpendicular to the axial direction are offset by opposing components.)
To reduce the amount of bounce.

(3) Since the spring adjuster 8 also serves as a fixed stopper element, the stroke of the movable core 4 can be arbitrarily variably adjusted by adjusting the amount of movement of the adjuster 8. When only the effect of (3) is expected,
This is possible without limiting the shapes of one end of the spring adjuster and one end of the movable core.

(4) The stroke operation of the movable core 4 is performed by a two-point guide mechanism in which the protrusion of the guide ring 19 is slid and guided in the fixed core 2 and the ball valve 13 is guided by the inner periphery of the swirler 16. The adoption guarantees a stable stroke operation.

FIGS. 4 and 5 show another embodiment of the present invention, in which only points different from the embodiment of FIG. 1 are shown.

That is, in the second embodiment shown in FIG. 4, a fixed stopper element 8 'provided at one end of the spring adjuster 8 is a spherical surface, and a stopper element (movable stopper element) 44 provided at one end of the movable core 4 side. Is also a spherical example,
Other configurations are the same as those in FIG. In this embodiment, the same effects as in the first embodiment can be obtained.

In the third embodiment shown in FIG. 5, the fixed stopper element 8 'provided at one end of the spring adjuster 8 has a tapered surface, and the movable stopper element has a tapered surface 44'. In addition, it is possible to mainly suppress the bounding of the movable core 4.

FIG. 6 is a longitudinal sectional view showing a fourth embodiment of the present invention.

In this embodiment, the one corresponding to the fixed-side stopper element 8 'is formed by one end (lower end) 2' of the fixed core 2, and the one corresponding to the movable-side stopper element 44 is opposed to the end face of the fixed core 2. The movable core 4 is formed by one end face 4 ′. Here, the upper half of the movable-side stopper element 4 'has a spherical surface, and the fixed-side stopper element 2' has a tapered surface. The return spring 6 includes a spring adjuster 8
And a spring receiving portion (recess) 47 formed at the center of the spherical surface 4 ′ of the movable core 4.

At the lower end 2 ′ of the fixed core 2, in addition to the tapered surface, a cylindrical wall portion 48 to which one end of the movable core 4 guides is provided.

Also in this example, the above (1),
The effects (2) and (4) are achieved.

FIG. 7 is a longitudinal sectional view showing a fifth embodiment of the present invention. Here, differences from the embodiment of FIG. 1 will be mainly described.

In this embodiment, as a stopper for regulating the stroke of the movable core 4 on the valve opening side, the fixed stopper element is constituted by one end (lower end) 2 'of the fixed core 2, and the movable stopper element is constituted by the movable core. 4 includes one end (upper end) 4 '.

A part (rod portion) 4C of the movable core 4 is inserted into one end of the fixed core 2 through the return spring 6, and a sphere 44 provided at the tip of the core part 4C is inserted into one end of the spring adjust 8. Locating the sphere 44
Are guided by the inner wall of the spring adjust 8 for movement in the axial direction. The diameter of the spherical body 44 is set to a diameter that can slide on the inner circumference of the spring adjuster 8.

The spring adjuster 8 has a fuel through hole 2.
1 is provided, the fuel passage 21 may be replaced with a slit 22 as shown in FIG.

In this embodiment, the stroke of the movable core 4 in the valve opening direction is restricted by the one end 2 ′ of the fixed core 2 and the one end 4 of the movable core 4.
′, The stopper elements 2 ′, 4 ′ are formed of flat surfaces. For the centering action, the valve 13
・ Spring adjuster 8 in addition to valve seat 7 ・ Movable core 4
The end surface (sphere) 44 also exhibits.

That is, when the axis of the movable core 4 is tilted, the spherical body 44 rotates around the inner periphery of the spring adjuster 8 and can be adjusted by itself. Therefore, both ends of the mover (the combined valve element and movable core) of the injector perform a self-centering action, thereby increasing the assembly accuracy of the valve element and the movable core, and performing a stable stroke operation.

Further, the guide function and alignment of the movable core and the valve body can be combined.

[0063]

According to the present invention, at least one of the functions of self-alignment of the mover of the injector and the amount of bounding is suppressed.
Even in the case of an injector such as a DI system used under severe conditions, it is possible to provide an injector that can guarantee a stable stroke operation and suppress the amount of bounce. Note that the injection of the present invention is not limited to the DI method.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of the present invention.

FIG. 2 is a partial perspective view of the embodiment.

FIG. 3 is a sectional view of a main part of the embodiment.

FIG. 4 is a sectional view of a main part showing a second embodiment of the present invention.

FIG. 5 is a sectional view of a main part showing a third embodiment of the present invention.

FIG. 6 is a longitudinal sectional view showing a fourth embodiment of the present invention.

FIG. 7 is a longitudinal sectional view showing a fifth embodiment of the present invention.

FIG. 8 is a partial perspective view showing another example of the spring adjuster used in the fifth embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Injector, 2 ... Fixed core, 3 ... Yoke, 4 ... Movable core, 5, 14, 40 ... Fuel passage, 6 ... Return spring, 7 ... Valve seat, 8 ... Spring adjuster, 8 '...
Fixed-side stopper element, 10: electromagnetic coil, 13: ball valve,
15: nozzle body, 16: swirler, 44: spherical body (movable side stopper element).

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02M 51/08 F02M 51/08 A K

Claims (7)

[Claims] 1. A fuel passage upstream of a valve seat, a fixed core and a movable core having a valve element are arranged in an axial direction, and at least a part of the fixed core and the movable core are housed in a yoke; When an electromagnetic coil provided around the fixed core is energized, the fixed core, the yoke, and the movable core form a magnetic circuit, and the movable core is attracted to the fixed core side against the force of the return spring to open the valve. In the injector, the stopper that regulates the amount of movement of the movable core in the valve opening direction includes a movable stopper element having a spherical surface, a fixed stopper element receiving the movable stopper element having a tapered surface,
The injector, wherein both the movable-side stopper element and the fixed-side stopper element are spherical, and both the movable-side stopper element and the fixed-side stopper element are tapered surfaces. 2. The fixed-side stopper element and the valve seat,
The injector according to claim 1, wherein the movable-side stopper element and the valve body have similar shapes. 3. The fixed core is formed of a hollow cylindrical body whose inside is a part of the fuel passage, and a return spring of the movable core is inserted into one end of the fixed core to adjust a spring force of the return spring. A hollow cylindrical spring adjuster is disposed in the fixed core, and one end of the spring adjuster forms the fixed-side stopper element, while one end of the movable core is inserted into the fixed core one end through the return spring. 3. The injector according to claim 1, wherein one end of the movable core forms the movable-side stopper element. 4. The injector according to claim 3, wherein a hole or a slit is formed in a side wall of the spring adjuster to guide fuel passing through the spring adjuster into the inside of the fixed core. 5. The injector according to claim 1, wherein the fixed-side stopper element is formed at one end of the fixed core, and the movable-side stopper element is formed at one end of the movable core. 6. A fixed core and a movable core having a valve body are provided in the axial direction with a fuel passage upstream of the valve seat, and at least a part of the fixed core and the movable core are housed in a yoke, When an electromagnetic coil provided around the fixed core is energized, the fixed core, the yoke, and the movable core form a magnetic circuit, and the movable core is attracted to the fixed core side against the force of the return spring to open the valve. In the injector, the fixed core is formed of a hollow cylinder having a fuel passage therein, and a return spring of the movable core is inserted into one end of the fixed core to adjust a spring force of the return spring. A spring adjuster is disposed in the fixed core, while a part of the movable core is inserted into one end of the fixed core through the return spring, and a part of the core is Injector, characterized in that spheres provided at the tip is positioned on the spring adjustment in one end are to receive the guide axial movement by the spring adjusting inner wall. 7. The valve body is a ball valve, which is guided in the axial direction by an inner wall of a central hole of a fuel swirler disposed upstream of a valve seat, and the guide and a part of the spherical body of the movable core are connected to the spring adjuster. 7. The injector according to claim 6, wherein the movable core is guided at both ends in the axial direction by the guide received inside.