JP2568515Y2 - Electromagnetic fuel injection valve - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coil and a fixed core fixedly arranged at a rear portion of a housing, and the fixed core.
Is stored in the housing so that it can move in the front-rear direction.
When the coil is excited, the coil is attracted to the fixed core.
Moving core and also in the housing in front of the fixed core
And movably stored in the front and rear direction.
So that the front end of the valve body can be seated.
A valve seat formed at the front of the housing, and fixed to the valve body
Provided between the cores and biasing the valve body forward to
In the demagnetized state of the coil, if the coil is held in a seated state,
The present invention relates to an electromagnetic fuel injection valve provided with a sleeper .

[0002] In this specification, "before" and "after" refer to
The front and rear sides of the housing, respectively.

[0003]

2. Description of the Related Art Conventionally, such an electromagnetic fuel injection valve is known, for example, from Japanese Utility Model Laid-Open Publication No. 1-176749.

[0004]

[Problems to be solved by the present invention]
The rear end of the valve body is integrally connected to the movable core by press-fitting and caulking into the movable core. When the valve is closed, the valve body and the movable core are integrally operated to close the valve. Has become. At this time, since the bouncing phenomenon that bounce when the front end portion of the valve body is seated on the valve seat occurs, prior to the valve body
Injecting the fuel before the end is completely seated in the valve seat makes low flow injection difficult. This is because the impact at the time of seating is large due to the relatively heavy weight of the valve element and the movable core due to the integral structure, and the lift amount of the valve element due to bouncing increases.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electromagnetic fuel injection valve capable of suppressing a valve body lift amount due to bouncing at the time of seating and enabling low fuel injection. And

[0006]

According to the present invention, in order to achieve the above object, a coil and a fixed core fixedly arranged at a rear portion of a housing, and a c at a front side of the fixed core.
It is stored movably in the front and rear direction in the housing and
In the excited state of the coil, the movable core attracted to the fixed core side
A, and in the front and rear direction inside the housing at the front side of the fixed core
Valve movably housed and extending in the front-rear direction
Housing so that the body and the front end of the valve body can be seated
And a valve seat formed at the front of the
And the valve body is urged forward to turn off the coil.
In the magnetic state, a first spring that holds the valve seat in a seated state is provided.
The electromagnetic fuel injection valve having a rear end portion of the valve body is fitted to the movable core as possible in the longitudinal direction-relative sliding between the movable core and the housing, the first field
A second spring is provided for urging the movable core backward with a spring load smaller than the spring, and is opposed to the urging force of the second spring.
A regulation for restricting a retreat limit position of the movable core with respect to the valve element.
A control means is provided at a front end surface of the valve body at a rear end thereof.
And a rearward direction provided on the movable core and capable of contacting the corresponding contact surface.
Of the contact surface and the receiving surface
In the meantime, the movable core opposes the urging force of the second spring.
Expands when moving forward and contracts when retracting
A damper chamber is provided between the fitting surfaces of the valve body and the movable core.
The damper chamber is formed in the housing.
The fuel passage is communicated with the fuel passage through a throttle .

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

FIGS. 1 to 4 show an embodiment of the present invention. FIG. 1 is a longitudinal sectional view of an electromagnetic fuel injection valve, and FIG.
FIG. 3 is an enlarged view of a main part of FIG. 1 in a valve closed state, FIG. 3 is a cross-sectional view corresponding to FIG. 2 when the movable core overshoots, and FIG.

[0009] First, in FIG. 1, the housing 1 of the electromagnetic fuel injection valve has a housing main body 2 is basically cylindrical, bottomed cylindrical valve which is fixed to the front end of the housing main body 2 The housing includes a housing and an electromagnetic unit housing fixed to the rear end of the housing body.

The housing body 2 comprises a rear large-diameter cylindrical portion 2a and a front small-diameter cylindrical portion 2b coaxially and integrally connected via a step 2c. A flange 5 extending radially inward is provided integrally on the inner surface of the intermediate portion of the portion 2b over the entire circumference.

[0011] valve housing 3 is formed in a bottomed cylindrical shape with a closed end of the front end side and has a diameter portion 3a which is enlarged stepwise to the rear end side. The enlarged diameter portion 3a of the valve housing 3 is fitted in the small diameter cylindrical portion 2b with a ring-shaped sealing plate 6 interposed between the flange portion 5 and the cap nut 7 engaged with the enlarged diameter portion 3a. by screwing the small-diameter cylindrical portion 2b outer surface, the valve housing 3 is fixed to the front end of the housing body 2.

The electromagnetic housing 4 includes a fixed core 8, a cylindrical yoke 9 surrounding the fixed core 8 coaxially, a connecting plate 10 connecting the fixed core 8 and the rear end of the yoke 9,
It has a connecting cylinder 11 coaxially connected to the rear end of the fixed core 8, and a yoke 9 is screwed into the large-diameter cylindrical portion 2 a of the housing body 2.

A coil 13 wound around a bobbin 12 is inserted between the fixed core and the yoke 9 of the electromagnetic unit housing 4 and connected to a nut 14 embedded in the bobbin 12 at a plurality of circumferential positions, for example, two places. The coil 13 is fixed to the electromagnetic unit housing 4 by screwing the screw members 15 penetrating through the respective members 10. From the bobbin 12, a pair of connection terminals 16 that pass through the connection plate 10 and protrude outward are drawn out. Further, a fuel passage 17 is provided coaxially in the connecting cylinder 11 and the fixed core 8, and a filter 18 is mounted on a rear end of the fuel passage 17.

Referring also to FIG.
The front end closing portion inner surface, and a valve seat 20 having ejection hole 19 at the center portion facing the rear, i.e. provided rearward, the valve
A needle-shaped valve body 21 formed to extend in the front-rear direction of the housing 3 and having a front end seated on the valve seat 20 to close the ejection hole 19 is provided between the housing 3 and the inner surface of the valve housing 3. It is inserted into the valve housing 3 so as to be movable in the front-rear direction so as to form an annular fuel passage 22. This valve 2
1 is provided with a pair of guide portions 23, 23 which are in sliding contact with the inner surface of the valve housing 3 and are spaced apart in the axial direction.
Flat notches 23a, 23a for avoiding blocking the fuel passage 22 are provided at a plurality of circumferential positions of the guide portions 23, 23, respectively.

The rear end portion of the valve body 21, which enters into the front end of the large-diameter cylindrical portion 2a of the housing body 2, the rear end of the valve body 21, located in front of the fixed core 8 A movable spring 24 is coupled and connected so as to allow relative movement in the axial direction within a limited range, and a first spring for urging the valve body 21 forward between the rear end of the valve body 21 and the fixed core 8. The movable core 24 is rearwardly provided between the flange 5 of the housing main body 2 and the movable core 24 , that is, the fixed core 8.
The second spring 26 biasing to the side is contracted, and the spring load of the first spring 25 is set to be larger than that of the second spring 26.

The movable core 24, the central portion of the disc portion 24a that faces the front end of the fixed core 8 and the yoke 9, which cylindrical portion 24b extending forward is formed by integrally connected to coaxially and, disc A plurality of through holes 27 are formed in the portion 24a to allow the fuel to flow. In the movable core 24, a large-diameter hole 28 on the rear side and a small-diameter hole 29 on the front side are formed coaxially with a step between them.
And a cylindrical sleeve 30 having an engagement flange 30a which engages with the step between the small-diameter hole 29 at the rear end is pressed into the small diameter hole 29 of the previous end from the movable core 24 so as to protrude forward.

The rear end of the valve body 21 is slidably fitted to the sleeve 30. An overhang flange 21 a provided at the rear end of the valve body 21 is It is inserted into the large-diameter hole 28 so as to face each other. Thus,
Locking collar 30a of sleeve 30 integral with movable core 24
A flat receiving surface 31 faces rearward, that is , is formed rearward, and a flat abutment that can abut on the receiving surface 31 is provided on the overhanging flange 21a at the rear end of the valve element 21. The surface 32 is formed facing forward , that is, facing forward . A fuel passage 1 formed at a rear end of the housing 1 is provided at a rear end of the valve body 21.
A communication passage 33 is formed in the housing 1 to communicate the fuel passage 22 with a fuel passage 22 formed in a front part of the housing 1. The receiving surface
31 and the contact surface 32 cooperate with each other to
Retraction limit of movable core 24 to valve element 21 against urging force
This constitutes the regulation means of the present invention for regulating the boundary position.

[0018] By the way, the valve the valve element 21 is that before the end seat 20
In a state where the movable core 24 is seated on the movable body 24, the receiving surface 31 is separated from the contact surface 32 of the valve body 21 and can be advanced as shown in FIG. A damper chamber 35 is formed between the contact surface 32 of the movable core 24 and the receiving surface 31 of the movable core 24. That is, the contact surface 32 and the receiving surface 3
1 between the movable core 24 and the urging force of the second spring 26.
Volume expansion when moving forward against
The contracting damper chamber 35 is provided between the valve body 21 and the movable core 24.
Are formed between the mating surfaces.

Moreover, the overhang flange 2 at the rear end of the valve body 21
And 1a external surface, between the inner surface of the large diameter hole 28 in the movable core 24, a small gap serving as a diaphragm 36 to let through the damper chamber 35 into the fuel passage 17 and 22 is formed in an annular shape.

Next, the operation of this embodiment will be described. In the state where the coil 13 is demagnetized, the valve body 21 urged by the first spring 25 having a large spring load causes the valve seat 20 to rotate.
The movable core 24 is urged by the second spring 26 having a small spring load, so that the receiving surface 31 abuts against the contact surface 32 of the valve body 21. It is in the position to touch. When the coil 13 is excited in this state, the movable core 24 is attracted to the fixed core 8 side, and the contact surface 32 is in contact with the receiving surface 31.
5 moves to the fixed core 8 side against the spring force of
Ejection hole 19 is opened before the end is moved away from the valve seat 20.
Therefore, the fuel filtered by the filter 18 passes through the fuel passage 1
7 through the communication passage 33 and the fuel passage 22,
Will be spouted from

The fuel injection amount is controlled by the duty ratio of the coil 13, that is, the change in the excitation time of the coil 13 within a certain time. When the coil 13 is changed from the excitation state to the demagnetization state, Since the suction force to the fixed core 8 is eliminated, the first spring 25 having a large spring load is used.
The valve body 21 by the spring force, press the movable core 24 is urged to the fixed core 8 side with a small second spring 26 of the spring load moves forward, the front end the valve seat 20 of the valve body 21 The seat 19 is seated and the ejection hole 19 is closed.

When the valve body 21 is seated on the valve seat 21, the valve body 21 is pressed by the first spring 25 having a large spring load, the weight of the valve body 21 itself is relatively small, and the fuel pressure is reduced. By acting in the seating direction, bouncing does not occur due to smooth seating on the valve seat 20.

On the other hand, the movable core 24 is movable relative to the valve body 21 in the axial direction, and when the valve body 21 is seated, the inertia force of the movable core 24 has a relatively small spring load.
6, the movable core 24 overshoots, and when the spring force of the second spring 26 returns, the receiving surface 31 of the movable core 24 collides with the contact surface 32 of the valve body 21, thereby causing the valve The body 21 separates from the valve seat 20 again. However, before the overshoot, since the contact surface 32 of the valve element 21 is in close contact with the receiving surface 31 of the movable core 24, the sticking occurs between the receiving surface 31 and the contact surface 32 due to the viscosity of the fuel. the damper chamber 35 formed between it and, also receiving surface 31 and the abutment surface 32 occurs
Communicates with the fuel passages 17 and 22 via the throttle 36.
Therefore, at the time of overshoot of the movable core 24, the overshoot speed of the movable core 24 is attenuated by the resistance due to the “sticking” and the damper effect of the damper chamber 35. The viscous drag due to the fuel associated with the operation described above also acts, so that the overshoot speed of the movable core 24 is further attenuated. As a result, the speed of collision of the movable core 24 with the valve body 21 at the time of return is suppressed, and the impact at the time of collision separates, so that the lift amount of the valve body 21 in the valve opening direction is suppressed to a small value.

Accordingly, as shown in FIG. 4A, the overshoot of the movable core 24 is attenuated, and the valve lift of the valve body 21 due to re-collision can be reduced.
Low fuel injection can be achieved. On the other hand, in the conventional device in which the valve element and the movable core are integrally connected, as shown in FIG. 4B, a bouncing phenomenon in which the valve lift is relatively large occurs, and it is difficult to inject a low flow rate. It becomes.

As another embodiment of the present invention, as shown in FIG. 5, a throttle 36 'for connecting the damper chamber 35 to the fuel passage 22 is formed directly at the rear end of the valve body 21. In this case, the same effect as in the above embodiment can be obtained.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and may be variously modified without departing from the present invention described in the claims for utility model registration. It is possible to make design changes.

[0027]

As described above, according to the invention] According to the present invention, the rear end portion of the valve body is fitted to the movable core as possible in the longitudinal direction-relative sliding, between the movable core and the housing, the first Spring
The second spring is provided for biasing remote with a small spring load the movable core to the rear, movable against the biasing force of the second spring
Regulation means for regulating the retreat limit position of the core with respect to the valve body
A front contact surface provided at the rear end of the valve body;
A rearward-facing receiver that is provided on the moving core and can abut against the corresponding contact surface
Surface, and between the contact surface and the receiving surface,
When the movable core moves forward against the biasing force of the second spring,
The damper chamber that expands and contracts when retracted,
And the movable core are formed between the mating surfaces of the movable cores.
The damper chamber restricts the fuel passage formed in the housing.
Since the communication through, while suppressing the bouncing upon seating of the valve element itself, possible to reduce the lift amount of the valve body caused by the re-collision of the valve element of the movable core by attenuating the overshoot speed of the movable core Thus, a small amount of fuel can be injected. And against the urging force of the second spring
Regulator that regulates the retreat limit position of the movable core with respect to the valve element
The step (the contact surface / receiving surface) is also used as the damper chamber forming means.
Therefore, the structure can be simplified accordingly.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an electromagnetic fuel injection valve according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of FIG. 1 in a valve closed state.

FIG. 3 is a cross-sectional view corresponding to FIG. 2 when the movable core overshoots.

FIG. 4 is a diagram showing operating characteristics in comparison with a conventional example.

FIG. 5 is a sectional view corresponding to FIG. 3 of another embodiment.

[Explanation of symbols]

Reference Signs List 1 housing 8 fixed core 17, 22 fuel passage 20 valve seat 21 valve body 24 movable core 24b cylindrical portion (second restricting means) 25 first spring 26 second spring 31 receiving surface (restricting means) 32 contact surface (restricting) Means) 35 Damper chamber 36, 36 'Restrictor

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Masami Nakamura 1-4-1 Chuo, Wako-shi, Saitama Pref. Honda Technical Research Institute Co., Ltd. (56) References JP-A-3-222862 (JP, A) 3-505769 (JP, A) Fully open Hei 1-176749 (JP, U) Really open 1983-64858 (JP, U)

Claims (1)

(57) [Scope of request for utility model registration] 1. A housing rear part fixedly arranged coil (13) and the fixed core (1) (8), that fixed
At the front side of the core (8), it is moved in the front-rear direction into the housing (1).
Movably housed and energized with the coil (13)
In the state, the movable core (24) sucked to the fixed core (8) side
And in the housing (1) in front of the fixed core (8).
And movably stored in the front and rear direction.
And a front end of the valve body (21)
Formed at the front of the housing (1) for seating
Between the valve seat (20), the valve body (21) and the fixed core (8)
And urges the valve body (21) forward to
When the coil (13) is in the demagnetized state, it comes into contact with the valve seat (20).
In a first spring (25) and the electromagnetic fuel injection valve having a holding the seat state, the rear end portion of the valve body (21) is fitted to the movable core (24) as possible in the longitudinal direction-relative sliding together it is, between the movable core (24) and housing (1),
A second spring (26) for urging the movable core (24) rearward with a smaller spring load than the first spring (25) is provided, and the movable spring (26) is pressed against the urging force of the second spring (26). core
(24) restricting the retreat limit position with respect to the valve body (21)
Regulating means provided at the rear end of the valve element (21).
Contact surface (32) and the movable core (24)
Receiving surface (3) that can contact the contact surface (32)
1), between the contact surface (32) and the receiving surface (31).
The movable core (24) is biased by the second spring (26).
Volume expansion when moving forward against
The shrinking damper chamber (35) is movable with the valve body (21).
A core (24) is formed between the mating surfaces of
The damper chamber (35) is provided with a fuel chamber formed in the housing (1).
Through the throttle (36, 36 ') to the feed passage (17, 22)
An electromagnetic fuel injection valve, which is in communication.