Fluid sprinkling – spraying – and diffusing – Including valve means in flow line – Reciprocating
Reexamination Certificate
2001-04-20
2003-11-18
Mar, Michael (Department: 3752)
Fluid sprinkling, spraying, and diffusing
Including valve means in flow line
Reciprocating
C239S533200, C251S129210, C137S625680
Reexamination Certificate
active
06648248
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates generally to a solenoid valve and a fuel injector which may be used to inject fuel into an internal combustion engine for automotive vehicles, and more particularly to an improved structure of a solenoid valve designed to minimizing undesirable loads on parts of the solenoid valve and a fuel injector using the same.
2. Background Art
In general, solenoid valves are used in fuel injectors of internal combustion engines. Such solenoid valves are designed to magnetically energize a stator installed in a housing to attract an armature, lifting up a valve member to open a valve hole. A maximum amount of lift of the valve member is fixed upon installation of the stator within the housing. For example, Japanese Patent First Publication No. 10-122086 discloses such a solenoid valve.
FIG. 6
shows one example of conventional solenoid valves for use in fuel injectors. The shown solenoid valve is constructed to be installed in a holder body
113
of a fuel injector. A control valve
106
is press fit within an armature
105
. The control valve
106
is disposed slidably in a bearing
110
and moved to open a valve hole
108
formed in a plate
111
when the armature
105
is attracted to a stator
104
. The bearing
110
is screwed into the holder body
113
to nip the plates
111
and
112
between the holder body
113
and the bearing
110
. The stator
104
is welded at portions, as indicated by A and B, to a casing
114
. A retaining nut
102
is screwed on a threaded cylinder
107
of the holder body
113
to hold the casing
114
and a spacer
109
between the end body
101
and the bearing
110
, thereby positioning the stator
104
relative to the plate
111
. This fixes the interval between the stator
104
and the valve hole
108
, thereby setting the maximum amount of lift of the control valve
106
.
The positioning of the stator
104
relative to the plate
111
, however, requires welding of the casing
114
and the stator
104
. The stator
104
, thus, needs to be made of a heat resisting material If the stator
104
is positioned in direct contact with the end body
101
and the spacer
109
in order to avoid thermal loads on the stator
104
, the compressive pressure produced by tightening the retaining nut
102
acts on the stator
104
. The stator
104
, thus, needs to be made of material which is tough and hard. Specifically, it is necessary to make the stators
104
of limited materials, which will be disadvantages in increasing the attractive force produced by the stator
104
and which may result in undesirable thermal deformation and physical breakage of the stator
104
.
SUMMARY OF THE INVENTION
It is therefore a principal object of the invention to avoid the disadvantages of the prior art.
It is another object of the invention to provide an improved structure of a solenoid valve designed to minimize undesirable loads on a stator and a fuel injector using the same.
According to one aspect of the invention, there is provided a solenoid valve which comprises: (a) a housing in which a fluid passage and a valve seat is formed; (b) a valve member disposed in the housing, when resting on the valve seat, the valve member closing the fluid passage, when leaving the valve seat, the valve member opening the fluid passage; (c) an armature connected to the valve member, the armature being movable in the same direction as that of movement of the valve member; (d) a stator attracting the armature to move the valve member, opening the fluid passage; (e) a coil producing an attractive force in the stator electromagnetically when the coil is energized; (f) a pressure-receiving mechanism provided in contact with the housing; (g) a fixing mechanism engaging the housing in contact with the pressure-receiving mechanism to press the pressure-receiving mechanism against the housing; and (h) an engaging mechanism holding the stator in engagement with the pressure-receiving mechanism without transmitting an external force acting on the pressure-receiving mechanism from the fixing mechanism and the housing.
In the preferred mode of the invention, the engaging mechanism includes a holding member which is formed integrally with the pressure-receiving mechanism on a side of a surface of the pressure-receiving mechanism opposite a housing-contacting surface and which has formed therein a groove with which the stator is fitted.
The pressure-receiving mechanism includes a cylindrical member having a flange which is formed on a valve seat side of the holding member integrally with the holding member and which is nipped between the housing and the fixing mechanism.
The stator has formed thereon a portion tapered toward the valve seat. The holding member is made of a cylinder which has an end portion remote from the valve seat, bent inwardly and a shoulder formed on an inner wall thereof, inclined to contact with the tapered portion of the stator.
The engaging mechanism includes a stopper made of cylindrical member which hits on one of the armature and the control valve when the armature is attracted by the stator and which has a damper flange. The stator is made of a hollow cylindrical member in which the stopper is disposed in contact of an end remote from the armature with the damper flange.
According to the second aspect of the invention, there is provided a fuel injector which comprises: (a) a nozzle valve working to open and close a spray hole selectively; (b) a nozzle body supporting the nozzle valve slidably; (c) a pressure chamber formed in the nozzle body, producing therein a fuel pressure working to urge the nozzle valve in a spray hole-closing direction; and (d) a solenoid valve working to control the fuel pressure in the pressure chamber. The solenoid valve includes: (a) a housing in which a fluid passage and a valve seat is formed; (b) a valve member disposed in the housing, when resting on the valve seat, the valve member closing the fluid passage, when leaving the valve seat, the valve member opening the fluid passage; (c) an armature connected to the valve member, the armature being movable in the same direction as that of movement of the valve member; (d) a stator attracting the armature to move the valve member, opening the fluid passage; (e) a coil producing an attractive force in the stator electromagnetically when the coil is energized; (f) a pressure-receiving mechanism provided in contact with the housing; (g) a fixing mechanism engaging the housing in contact with the pressure-receiving mechanism to press the pressure-receiving mechanism against the housing; and (h) an engaging mechanism holding the stator in engagement with the pressure-receiving mechanism without transmitting an external force acting on the pressure-receiving mechanism from the fixing mechanism and the housing.
In the preferred mode of the invention, the engaging mechanism includes a holding member which is formed integrally with the pressure-receiving mechanism on a side of a surface of the pressure-receiving mechanism opposite a housing-contacting surface and which has formed therein a groove with which the stator is fitted.
The pressure-receiving mechanism includes a cylindrical member having a flange which is formed on a valve seat side of the holding member integrally with the holding member and which is nipped between the housing and the fixing mechanism.
The stator has formed thereon a portion tapered toward the valve seat. The holding member is made of a cylinder which has an end portion remote from the valve seat, bent inwardly and a shoulder formed on an inner wall thereof, inclined to contact with the tapered portion of the stator.
The engaging mechanism includes a stopper made of cylindrical member which hits on one of the armature and the control valve when the armature is attracted by the stator and which has a damper flange. The stator is made of a hollow cylindrical member in which the stopper is disposed in contact of an end remote from the armature with the damper flange.
According to the third
Adachi Naofumi
Murakami Motoichi
Ohata Koichi
Denso Corporation
Mar Michael
Nguyen Dinh Q.
Nixon & Vanderhye PC
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