CN201351562Y

CN201351562Y - Needle valve structure of fuel injector

Info

Publication number: CN201351562Y
Application number: CNU2008200610657U
Authority: CN
Inventors: 王志华; 邵康; 江明辉
Original assignee: United Automotive Electronic Systems Co Ltd
Current assignee: United Automotive Electronic Systems Co Ltd
Priority date: 2008-12-25
Filing date: 2008-12-25
Publication date: 2009-11-25
Anticipated expiration: 2018-12-25

Abstract

The utility model discloses a needle valve structure of a fuel injector of a gasoline engine; the needle valve structure comprises a needle valve stem and an armature, wherein the armature and the needle valve stem are movably sheathed. In the needle valve structure of the non-fixed armature, in the process of starting the needle valve, as the armature is separated from the upper end surface of a baffle ring, the needle valve can make a fast response; while in the process of closing the needle valve, as the armature is separated from the lower end surface of a spacer sleeve, the impact force between a valve ball and a valve seat can be reduced, and the wear between the valve ball and the valve seat can be decreased.

Description

The needle valve structure of oil sprayer

Technical field

The utility model relates to a kind of needle valve structure that is applicable to petrol engine fuel injector.

Background technique

The light needle-valve of design oil sprayer is the heat subject of always studying, and for impact force and the wearing and tearing of less oil-fuel injector needle-valve to valve seat, research alleviates the quality of needle-valve pipe or armature usually.For high pressure directly jetting gasoline engine oil sprayer, because jet pressure can reach 150bar or 200bar, under high oil pressure effect, for oil sprayer is not leaked, the main spring impacting force is big, it is big to cause oil-fuel injector needle-valve that valve seat is impacted like this, serious wear, and owing to the impact of needle-valve and valve seat makes the needle-valve bounce-back cause leaking.Fig. 6 is the needle valve structure of existing a kind of fixed armature, leaks for fear of oil sprayer, and the main spring impacting force, needle-valve is big to the impact force of valve seat, easily causes the needle-valve bounce-back, and the oil sprayer accuracy is uncontrollable.

The model utility content

The technical problems to be solved in the utility model provides a kind of needle valve structure of oil sprayer, and it can reduce the impact wear between needle-valve and the valve seat, avoids the needle-valve bounce-back.

For solving the problems of the technologies described above, the needle valve structure of oil sprayer of the present utility model comprises Needle shaft and armature, and wherein said armature and described Needle shaft are for socket-connecting movably.

The needle valve structure of oil sprayer of the present utility model, the needle valve structure of employing on-fixed armature in the needle-valve opening process, because armature separates with the baffle ring upper-end surface in the needle valve structure, can make the needle-valve response fast; And close in the closed procedure at needle-valve, because of armature separates with the interstage sleeve lower end surface, can reduce the impact force between valve ball and the valve seat, and help reducing wearing and tearing between valve ball and the valve seat, the noise that valve ball and valve seat produce also can reduce, meanwhile because the needle-valve quality of on-fixed armature alleviates relatively, can avoid the needle-valve bounce-back, oil spout is more accurate.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the utility model is described in further detail:

Fig. 1 is the schematic perspective view of needle valve structure of the present utility model;

Fig. 2 is the floor map of needle valve structure of the present utility model;

Fig. 3 is the partial enlarged drawing of needle valve structure of the present utility model;

Fig. 4 is the working state schematic representation of needle valve structure of the present utility model;

Fig. 5 is the stressed schematic representation of needle valve structure of the present utility model;

Fig. 6 is the stressed schematic representation of existing needle valve structure.

Embodiment

Fig. 1 to Fig. 3 is the needle valve structure of oil sprayer of the present utility model, also can be described as the needle valve structure of on-fixed armature, and wherein 3 armature no longer have been fixedly attached on the Needle shaft 5 (being generally welding).Needle valve structure of the present utility model, in preparation process, earlier baffle ring 4 is welded on the Needle shaft 5 on the suitable position, the socket upper armature 3 again, return spring 2 overlapped after on the interstage sleeve 1, be inserted on the Needle shaft 5 more together, after adjusting the free travel of armature 3, interstage sleeve 1 is fixed on the Needle shaft 5 (is generally welding), at last valve ball 6 is welded on the other end of Needle shaft 5.The maximum difference of above-mentioned needle valve structure of the present utility model and existing general needle valve structure for armature for to be socketed on the Needle shaft movably.

The needle-valve of on-fixed armature of the present utility model is opened working principle: as can be seen from Figure 4, there is individual main spring 7 interstage sleeve 1 upper-end surface in the needle valve structure of on-fixed armature, and this main spring 7 is provided with certain pretightening force and is used to push down Needle shaft 5 and does not lift off a seat 8 to guarantee valve ball 6 at fuel pressure effect lower valve ball 6 usually.When oil sprayer needs work, ECU (electronic controller) gives signal, solenoid valve produces magnetic force under the function of current, magnetic force is not constant, increase gradually, armature 3 is under the effect of magnetic force, overcoming the gravity of self and the active force of return spring 2 begins toward the motion of interstage sleeve 1 direction, and the pretightening force of main spring 7 is much larger than the gravity of any parts of the needle-valve of on-fixed armature and the active force of return spring 2, valve ball 6 still is parked on valve seat 8 sealing surfaces, and when moving to interstage sleeve 1 lower end surface, armature 3 and interstage sleeve 1 fit together, the active force that this moment, magnetic force was large enough to overcome main spring 7 makes valve ball 68 sealing surfaces of lifting off a seat, and fuel oil sprays from spray orifice.

And the needle-valve of on-fixed armature of the present utility model is closed working principle and is: when oil sprayer need quit work, ECU gives halt instruction, failure of current, solenoid valve magnetic force weakens, under the active force of main spring 7, force Needle shaft 5 and armature 3 together toward the motion of valve seat 8 directions, when valve ball 6 contacts with valve seat 8, Needle shaft 5 is under the effect of main spring 7, with valve ball 6 fuel sealing is lived, armature 3 separates with interstage sleeve 1 lower end surface simultaneously, does relatively independent motion, finally is fitted on the upper-end surface of baffle ring 4 under return spring 2 effects.

The needle-valve opening process of on-fixed armature of the present utility model, owing to armature 3 separates with the upper-end surface of baffle ring 4, can be so that the response of the needle-valve of on-fixed armature be fast.Because the magnetic force that armature is subjected to changes, stressed complexity is analyzed response problem from qualitative angle.F0 changes as follows:

F magnetic force from 0 to F0 again to Fmax (Fmax＞F0);

Pulsewidth time ti from 0 to t0 again to tmax;

For fixing armature structure, when ti=t0, find out that from the needle-valve free-body diagram of Fig. 6 existing fixed armature F makes a concerted effort=F0-F0=0, valve ball 6 will leave but also not leave reference level (valve seat 8 in other words).

For revocable armature needle valve structure (see figure 5), when ti=t0, make armature 3 just in time fit by the free travel of adjusting armature with interstage sleeve 1 lower end surface, this moment, magnetic force also was to equal F0, and armature 3 has had certain kinetic energy, therefore valve ball 6 will leave reference level, that is to say that the response of on-fixed armature needle valve is fast relatively, certainly regulate suitable armature free travel, can be so that armature 3 fits with interstage sleeve 1 lower end surface before t0 and has enough energy to make valve ball 6 leave reference level (valve seat 8).

The needle-valve of on-fixed armature closes closed procedure, when valve ball 6 contacts with valve seat 8, armature this moment separates with interstage sleeve 1 lower end surface, needle valve structure with respect to fixed armature, the on-fixed armature needle valve cuts the armature all-mass, and the quality of armature as a rule accounts for about 55% of all quality, therefore design for the on-fixed armature needle valve, this needle-valve quality alleviates greatly, also is to say that the impact force between valve ball 6 and the valve seat 8 is less, helps reducing the wearing and tearing between valve ball 6 and the valve seat 8, the noise that valve ball 6 and valve seat 8 produce also can reduce, meanwhile because the needle-valve quality of on-fixed armature alleviates relatively, can avoid the needle-valve bounce-back, oil spout is more accurate.

Claims

1, a kind of needle valve structure of oil sprayer, described needle valve structure comprises Needle shaft and armature, it is characterized in that: described armature and described Needle shaft are for socket-connecting movably.

According to the described needle valve structure of claim 1, it is characterized in that 2, described needle valve structure further comprises: baffle ring, be positioned under the described armature, be socketed on the described Needle shaft and then fixedly connected with described Needle shaft; Return spring is positioned on the described armature, and described return spring one end is socketed with interstage sleeve, described return spring and described interstage sleeve all with described Needle shaft socket, described interstage sleeve is fixedlyed connected with described Needle shaft; Valve ball is positioned at Needle shaft one end of described baffle ring one side and fixedlys connected with described Needle shaft.

3, according to the described needle valve structure of claim 2, it is characterized in that: the fixed position of described interstage sleeve and described Needle shaft is set by the free travel of described armature.