Patent Application
20060169936
1. Field of the Invention
The present invention relates to solenoid valves which control a fluid flow by opening and closing a valve in response to the application of a current.
2. Description of Related Art
A normally closed-type, solenoid valve (e.g., an electromagnetic valve), which is opened in response to the attraction of a movable iron core (e.g., an armature) to a fixed iron core (e.g., a core) magnetized by the application of a current to a surrounding coil, is frequently used as a valve for controlling the opening and the closing of a fuel supply, pipe line and a working fluid, supply path of a vehicle. On the other hand, a normally open-type, solenoid valve which is normally opened and is closed when electricity is applied, also is known, for example, as described in Japanese Unexamined Patent Publication No. H09-229229. The normally open-type, solenoid valve has an advantage that a flow rate may be maintained and that an engine may be operated continuously even when a current supply for driving is intermittent or interrupted.
In the solenoid valve used for controlling the fluid flows as described above, a magnitude (e.g., a width) of a valve stroke generally is limited, a width of a gap formed between a valve body and a valve seat and constituting a flow path may become excessive due to a slight variation part dimensions and a slight inaccuracies at the time of assembling, or a change in width may occur due to a long-term use, whereby an initially expected flow rate may not be obtained or maintained.
With respect to these problems, Japanese Unexamined Patent Publication No. H05-18473 describes a configuration, such that a temporary spacer is interposed between a fixed iron core and a movable iron core when the solenoid is assembled, and a desired air gap is formed between the fixed iron core and the movable iron core when solenoid assembly is completed. Further, Japanese Unexamined Patent Publication No. H07-27246 describes a configuration, such that various dimensions constituting a valve stroke width are measured when assembling a normally open-type, solenoid valve, and a desired valve stroke width is set by selecting a shaft receiving plate having a width corresponding thereto.
On the basis of these configurations, even if the precision with which parts are manufactured and assembled is not high, a desired valve stroke width may be achieved, and an accurate flow rate may be obtained, when the valve is opened. Nevertheless, in the configuration described in Japanese Unexamined Patent Publication No. H05-18473, the temporary spacer must be attached and detached when assembling the valve, and the number of assembly steps is increased, resulting in a cost increase. On the other hand, in the configuration described in Japanese Unexamined Patent Publication No. H07-27246, a plurality of dimensions must be accurately measured before assembling the valve, and manufacturing time is increased significantly.
Further, among both of these configurations, when the width of the gap formed by the valve seat and the valve body is changed through use of the solenoid valve over a long term, and the flow rate is changed to a different flow rate from the original or initial flow rate when the valve was opened, it is difficult to adjust to this situation.
The present invention solves the problems described above, and a technical advantage of the present invention is to provide a solenoid valve in which a valve stroke width may be set readily to obtain a desired flow rate, and the flow rate may return to an initial or original flow rate by making it possible to adjust the flow rate even when the original flow rate may not be obtained or maintained due to wear.
In order to solve the problems described above, a solenoid valve is provided comprising:
a drive portion comprising a bobbin comprising a slidable hole formed therethrough, a fixed iron core disposed in the slidable hole and a movable iron core slidably disposed within the slidable hole; and
a valve function portion comprising a valve body extending from the movable iron core and disposed in a leading end of a valve shaft passing through the fixed iron core and a valve seat with which the valve body is brought into close contact and from which the valve body is separated,
wherein a magnitude of a gap formed between the valve body and the valve seat is adjustable when the valve is opened, by means of a flow rate adjusting screw, which may be adjusted from an outer side in a rear end of the solenoid valve and comprises a leading end protruding into the slidable hole to bring the leading end into contact with a rear end surface of the movable iron core when the valve is opened, thereby adjusting a protrusion amount of the screw into the leading end of the slidable hole.
Accordingly, a valve stroke width may be adjusted precisely without requiring a precise dimensional accuracy in valve components and a precise accuracy in assembling the valve, and even when a width of an original gap formed between the valve body and the valve seat may become excessive due to use and may generate a flow rate, it is possible to return to the initial gap width only by turning the flow rate adjusting screw.
On the other hand, a solenoid valve may be provide, comprising:
a valve function portion comprising a bobbin, a fixed iron core disposed to be brought into close contact with the bobbin or integrally formed with the bobbin and a movable iron core to be slidable along an axial direction in an exciting end surface side of the fixed iron core; and
a valve function portion comprising a valve shaft extended from the movable iron core toward a leading end, a valve body disposed in a leading end of the valve shaft and a valve seat with which the valve body is brought into close contact and from which the valve body is separated,
wherein a magnitude of a gap formed between the valve body and the valve seat is adjustable when the valve is opened, by means of a flow rate adjusting screw adjustable from an outer side in a rear end of the solenoid valve and protruding to an inner portion of the valve to bring the leading end into contact with a rear end surface of the movable iron core when the valve is opened, thereby adjusting a protrusion amount of the screw into the leading end of the slidable hole. Accordingly, a solenoid valve of a face-type, in which the movable iron core is formed in a disc shape and is not accommodated in an inner peripheral side of the bobbin, also may be utilized.
Further, when the solenoid valve structured is configured as a normally open-type, solenoid valve, which is opened by forming a gap between the valve body and the valve seat when the solenoid valve is not energized, and is closed when the movable iron core is drawn to the fixed iron core when the solenoid valve is energized, a valve open state may be maintained even when the current applied to drive the solenoid valve is intermittent or interrupted. Alternatively, when the solenoid valve is configured as a normally closed-type, solenoid valve which is closed when the solenoid valve is not energized, and is opened by creating a gap between the valve body and the valve seat when the movable iron core is drawn to the fixed iron core when the solenoid valve is energized, the fluid within the pipe may be sealed, such that when the valve is closed, the fluid is not delivered.
Further, when the flow rate adjusting screw is formed of a non-magnetic material, the flow rate adjusting screw is not excited by applying the current to the drive portion. Thus, valve operation is not affected by a movement of the movable iron core.
Further, when a seal means for making an inner portion airtight and liquid-tight with respect to an outer portion is provided in a through hole formed in an outer side in a rear end of the solenoid to which the flow rate adjusting screw is inserted, air and liquid may be prevented from intruding from the outer portion so as to well maintain the valve function and the nature of the fluid without requiring tight tolerances between the flow rate adjusting screw and the through hole. When the seal means comprises an O-ring disposed with respect to the flow rate adjusting screw within the through hole to which the flow rate adjusting screw is inserted, a sealing function may be achieved without increasing costs.
In accordance with the present invention having the uncomplicated structure as described above, a valve stroke width may be achieved to maintain a desired flow rate when assembling the solenoid valve easily and at a low cost. Further, even when the width of the gap formed between the valve body and the valve seat is changed due to the use, and the original flow rate may remain unobtainable, the original flow rate may be achieved on the basis of a straightforward operation of only turning the flow rate adjusting screw so as to adjust flow.
Further objects, features, and advantages of the present invention will be understood from the following detailed description of preferred embodiments of the present invention with reference to the accompanying figures.
Embodiments of the invention now are described with reference to the accompanying figures, which are given by way of example only, and are not intended to limit the present invention.
A description is given below of embodiments in accordance with the present invention and with reference to the accompanying drawings. In the present invention, as a matter of convenience, the member magnetized by energizing an electric conduction coil of a bobbin may be referred to as a fixed iron core, and the member sliding in an axial direction in an inner portion of a solenoid valve and drawn by a magnetic force of the fixed iron core may be referred to as a movable iron core. Nevertheless, the members are not limited to iron as long as they are formed of a magnetic material. Further, in the following description, the left side in the drawing is a leading end side, and the right side is a rear end side.
FIGS. 1 to 3 show cross-sectional views of a normally open-type, solenoid valve 1 corresponding to a first embodiment in the present invention. Normally open-type, solenoid valve 1 may be disposed in a fuel supply, pipe path of an engine and may be used as a fluid control valve for a supplied fuel. A right side portion in
Drive portion 10 comprises a slidable hole 111 formed through the center, and comprises an electric conduction coil 120 formed by winding an electric conduction line or wire around an outer periphery of a bobbin 110 corresponding to a main body portion of solenoid valve 1. Electric conduction coil 120 is configured to excite in response to a current, such as a battery current, applied via wiring (not shown). Further, an outer side of bobbin 110 is provided with a cover body 130 covering bobbin 110 and sealing an inner portion of bobbin 110. An substantially columnar, movable iron core 140 is inserted slidably into slidable hole 111 and extends along a center axis. Further, an substantially cylindrical, fixed iron core 150 is fixed within leading, side opening portion of slidable hole 111, such that about one half of core 150 is fitted and inserted towards a rear end.
A valve shaft 160 is disposed to protrude toward a leading end from a leading end surface of movable iron core 140 and is inserted into a through hole 170 formed through fixed iron core 150. Through hole 170 is formed as a guide hole for sliding valve shaft 160 along a center axis of fixed iron core 150 and slidable hole 111. Further, a flow rate adjusting screw 180 made of a resin or similar non-magnetic material is inserted into a rear end of slidable hole 111 from a rear end, outer side surface of bobbin 110 via a threaded hole 112 and passes there through in to slidable hole 111 to protrude toward the leading end. Further, an O-ring 190 is fitted between a ring groove 113 formed in an inner peripheral flat portion of threaded hole 112 and an outer peripheral flat portion of flow rate adjusting screw 180. Thus, an inner portion of slidable hole 111 is in airtight and liquid-tight separation from an outer portion.
Valve function portion 20 comprises a tube body 210 in which a slidable hole 211 is formed in an inner portion along a center axis, an outlet hole 212 is formed to pass between an inner side and an end surface of a leading end, and an inlet hole 213 is formed to pass between an inner side and an outer periphery of a leading end. A substantially columnar needle 230 is fixed to the leading end side of valve shaft 160 and is formed with a conical shaped tip in a leading end. Substantially columnar needle 230 is disposed slidably within slidable hole 211 and provided with a flange 220 in a rear end. Further, the leading end, conical portion of needle 230 is formed as a valve body 240 and creates an opening and closing mechanism together with an inner opening end of a tubular valve seat 250. Valve body 240 is inserted into outlet hole 212, and is urged in a valve opening direction by a spring 260.
Solenoid valve 1 is structured as described above, and is formed as a less complicated structure which does not result in a cost increase for manufacture in comparison with known, general solenoid valves.
A description now is given of operation of solenoid valve 1 with reference to
Accordingly, because a stroke width may be adjusted appropriately to a desired flow rate without requiring a high degree of dimensional accuracy in the components and without requiring a high degree of accuracy in assembling the components of solenoid valve 1, and because a temporary spacer need not be attached and detached and a plurality of positions need not be accurately measured, increases in the time and cost for manufacturing may be avoided or reduced.
Needle valve 230 is urged rearward by spring 260 in valve function portion 20 as described above when the drive portion 10 is not energized, whereby valve body 240 is separated from valve seat 250 at a predetermined width set by flow rate adjusting screw 180. Thus, a gap may be formed (
Further, fixed iron core 150 is magnetized by energizing drive portion 10, and movable iron core 140 is drawn to fixed iron core 150. Accordingly, needle 230 moves forward against a restraining force of spring 260, and valve body 240 is brought into close contact with valve seat 250 to close the valve (
A description now is given of a situation in which the flow rate adjustment of solenoid valve 1 is executed, with reference to
The gap formed between valve body 240 and valve seat 250 is widened to a width X by moving the flow rate adjusting screw 180 rearward by the distance X (
With respect to the difference in the operation surface between the normally open-type, solenoid valve and the normally closed-type, solenoid valve, the normally open-type, solenoid valve is advantageous in that the valve open state may be maintained even when the current application for driving the solenoid valve is intermittent or interrupted, and the normally closed-type, solenoid valve is advantageous in that the fluid may be sealed within the pipe during periods in which the fluid is not delivered.
In the embodiments described above, each of the solenoid valves is primarily in terms of the structures used as the cutoff mechanisms in the fuel supply pipe of the engine. Nevertheless, the structures are not limited to this function. For example, the solenoid valve may be used as the opening and closing mechanism of the supply pipe line for the working fluid, and the operations and effects described above may be expected in the same manner. Further, the flow rate adjusting screw is not limited to manufacture from resin, but may be made of a non-metallic metal, such as an aluminum, or another non-magnetic material.
Although embodiments of the present invention have been described in detail herein, the scope of the invention is not limited thereto. It will be appreciated by those skilled in the art that various modifications may be made without departing from the scope of the invention. Accordingly, the embodiments disclosed herein are only exemplary. It is to be understood that the scope of the invention is not to be limited thereby, but is to be determined by the claims which follow.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2005020567 | Jan 2005 | JP | national |
