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Electromagnetic fuel pumpElectromagnetic fuel pump description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20080044301, Electromagnetic fuel pump. Brief Patent Description - Full Patent Description - Patent Application Claims
BACKGROUND OF THE INVENTION [0001]1. Field of the Invention [0002]The present invention relates to an electromagnetic fuel pump used for delivering a liquid fuel reserved in a fuel tank to a combustion apparatus, more particularly to a plunger type electromagnetic fuel pump. [0003]2. Description of Related Art [0004]Conventionally, a fuel pump has been employed as a fuel delivery means of a combustion apparatus such as an oil heater, an engine or the like, and as described in Japanese Unexamined Patent Publication No. 5-79452 and Japanese Unexamined Patent Publication No. 2002-39067, there has been generally widely spread a plunger type electromagnetic fuel pump which can achieve a stable fuel delivery and an accurate flow rate control by repeating generation and elimination of a magnetic force to slidably reciprocate a plunger urged by a return spring for pressurizing a fuel in a fuel passage. [0005]In the plunger type electromagnetic fuel pump, for example, as shown in a longitudinal cross sectional view, shown in FIG. 4, of an electromagnetic fuel pump 2 used for supplying a liquid fuel such as a gasoline or the like to an engine, a plunger 3 constituted by a magnetic material and arranged slidably in a cylinder 4 is moved backward on the basis of a magnetomotive force caused by a current application to an electromagnetic coil 5 against an urging force of a return spring 41, and a check valve 30 provided in a leading end side of the plunger 3 is opened so as to introduce the fuel into a pressurizing chamber 6 formed in a front side of the plunger 3 from an intake port 44 formed in a proximal end of the cylinder 4. [0006]Further, the urging force of the return spring 41 overcomes the magnetic force by reducing or stopping the current to the electromagnetic coil 5, and the plunger 3 is moved forward, thereby pressurizing the fuel in the pressurizing chamber 6 and a check valve 70 arranged on the downstream side of the pressurizing chamber 6 is opened. The fuel is delivered toward the engine from a discharge port 42 formed in the leading end of the cylinder 4 by repeating the operation mentioned above. [0007]In the plunger type electromagnetic fuel pump 2 for the gasoline engine mentioned above, as shown in an enlarged partial view of the plunger 3 in FIG. 5, the structure is such that the check valve 30 is provided in a leading end side (a discharge side) of a fuel passage 38 passing through the plunger 3, a valve member 32, a return spring 33 and a spring guide 34 are inserted, and the spring guide 34 is fixed to the plunger 3 by a fastening clip 35 corresponding to a fixing means having a repulsion force of a spring steel. Further, the check valve 70 having a check valve structure similar to the check valve 30 is provided in the cylinder 4 on the downstream side, and the pressurizing chamber 6 is formed between the check valves 30 and 70. [0008]In this case, in a fixing structure of the valve members 32 and 32 constituting the conventional check valves 30 and 70 to the mounting position, the spring guide 34 and the fastening clip 35 for fixing the spring guide 34 are formed as separate parts, thereby causing an increase in a number of the parts of the electromagnetic fuel pump. Further, when the fastening clip 35 is inserted in the plunger 3 so as to be fixed, when manufacturing the electromagnetic fuel pump 2, there is a case that an inner peripheral surface of the mounting position of the plunger 3 is scraped by the fastening clip 35 and a chip is generated. Since there is a case that this causes a seat failure of the valve member 32, a cleaning step for removing the chip after assembling is necessary. Accordingly, these matters cause a cost increase of the electromagnetic fuel pump. SUMMARY OF THE INVENTION [0009]The present invention intends to solve the problem mentioned above, and an object of the present invention is to achieve a cost saving by reducing a number of parts relating to a layout of a check valve and making a cleaning step after assembling unnecessary, in a plunger type electromagnetic fuel pump. [0010]In accordance with the present invention, there is provided an electromagnetic fuel pump comprising: a cylinder having a discharge port provided with a check valve and an intake port on a proximal end side thereof; a plunger slidably fitted in the cylinder, the plunger having a fuel passage formed along an axis thereof and provided with a check valve therein on a leading end side thereof; a return spring arranged on the proximal end side between the plunger and the cylinder for urging the plunder in a leading end side direction; and an electromagnetic coil arranged on the outside of the cylinder, a current application to the electromagnetic coil being controlled so as to repeat generation and elimination of a magnetic force to cause the plunger to slidably reciprocate for delivering a fuel under pressure; wherein at least the check valve provided in the plunger has a spring retaining member having a spring guide retaining a discharge side of the return spring urging a valve member thereof in a valve closing direction, and a fixing structure to the discharge port of the plunger or the cylinder. [0011]As mentioned above, since the return spring guide retaining the valve member of the check valve via the return spring is integrally provided with the fixing structure for fixing it so as to form the spring retaining member, any fastening clip constituted by an independent part is not necessary as the fixing member, so that it is possible to avoid generation of a chip caused by an installation of the fastening clip as well as it is possible to reduce a number of the parts, thereby making a cleaning work after assembling unnecessary. [0012]Further, in the case that the check valves provided with the spring retaining members are provided at two positions on an upstream side and on a downstream side of the pressurizing chamber, a delivery efficiency of the fuel is excellent and the parts reduction can be achieved at two positions. [0013]Further, in the electromagnetic fuel pump mentioned above, in the case that the fixing structure of the spring retaining member comprises an outer peripheral side extending from the proximal end side of the spring guide in a centrifugal direction with respect to a center axis of the fuel passage, the outer peripheral side of the spring retaining member being fitted in an inner peripheral surface of the mounted position in close contact therewith, the spring retaining member being fixed on the basis of an elastic repulsion force of the fixing structure itself, it is possible to easily form by a comparatively simple structure. [0014]Further, in the electromagnetic fuel pump mentioned above, in the case that the spring retaining member is made of a synthetic resin having an appropriate elasticity, it is easy to have a suitable elastic deformable performance as well as it is easier to form, and it is possible to easily and securely fix without requiring any high-level molding precision. [0015]In accordance with the present invention in which the return spring guide retaining the check valve via the return spring is integrally provided with the fixing structure for fixing it to the mounting position, it is possible to omit the cleaning step after assembling as well as it is possible to reduce the number of the parts necessary in conjunction with the layout of the check valve, and it is possible to easily achieve the cost saving. BRIEF DESCRIPTION OF THE DRAWINGS [0016]FIG. 1 is a longitudinal cross sectional view showing an embodiment in accordance with the present invention; [0017]FIG. 2 is an enlarged partial view of the leading end side of the plunger in FIG. 1; [0018]FIG. 3A is a side elevational view of the spring retaining member, as seen from the upstream side of the fuel passage; [0019]FIG. 3B is a cross sectional view, taken along the line X-X in FIG. 3A; [0020]FIG. 4 is a longitudinal cross sectional view showing a prior art; and [0021]FIG. 5 is an enlarged partial view of the leading end side of the plunger in FIG. 4. Continue reading about Electromagnetic fuel pump... Full patent description for Electromagnetic fuel pump Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Electromagnetic fuel pump patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Electromagnetic fuel pump or other areas of interest. ### Previous Patent Application: Air pump Next Patent Application: Electromagnetic fuel pump Industry Class: Pumps ### FreshPatents.com Support Thank you for viewing the Electromagnetic fuel pump patent info. IP-related news and info Results in 0.72884 seconds Other interesting Feshpatents.com categories: Qualcomm , Schering-Plough , Schlumberger , Seagate , Siemens , Texas Instruments , 174 |
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