JP2023183866A - Injector for gas fuel - Google Patents

Abstract

To provide an injector for gas fuel that prevents excessive wear of a valve body due to increased impact load between the valve body and a valve seat during the valve-closing operation, thereby sustaining the sealing efficacy of an on-off valve for an extended time.SOLUTION: An electromagnetic driven injector for gas fuel 1 includes an on-off valve 30 consisting of a valve seat 40 with a valve hole 41 penetrating it, and a valve body 50 for opening and closing the valve hole 41. In the valve seat 40, an annular projection 60 consisting of an inner annular protrusion 70 and an outer annular protrusion 80, arranged in concentric dual layers, surrounds an opening end 42 of the valve hole 41 and is capable of making contact with the valve body 50. In the closed valve state, a top edge 71 of the inner annular protrusion 70 and a top edge 81 of the outer annular protrusion 80, respectively, make contact with the valve body 50.SELECTED DRAWING: Figure 1

Description

The present invention relates to a normally closed gas fuel injector for injecting and supplying a flow rate of gas fuel required by an engine driven by gas fuel such as LPG.

Examples of electromagnetically driven injectors that attract a movable iron core by energizing and energizing an electromagnetic coil, open an on-off valve, and supply fuel include, for example, JP-A-2010-096073 (Patent Document 1) and JP-A-2020- BACKGROUND ART A gaseous fuel injector 1a as shown in FIG. 4, which is described in Japanese Patent No. 037927 (Patent Document 2), is widely known.

In this gaseous fuel injector 1a, a moving core 23a with a valve body 50a fixed to the bottom side is supported at the center of a disc-shaped leaf spring 22a below a fixed core (center rod) 26a. A valve rubber 51a provided as a seal portion on the lower surface of the valve body 50a is attached to a valve seat with a valve hole 41a opened in the center by the biasing force of a coil spring 21a interposed between the fixed iron core 26a and the movable iron core 23a. The valve is of a normally closed type that maintains the closed state by pressing against the annular seat surface 60a of the valve 40a.

However, in such conventional injectors, when the gaseous fuel supply pressure is high, the impact load between the valve body and valve seat during valve closing operation is significantly greater than when the supply pressure is low. As a result, the valve rubber portion of the valve body tends to wear excessively, resulting in problems such as a decline in the pressure regulation performance of the injector and leakage of gaseous fuel in a relatively short period of time.

In order to solve this problem of wear in the valve body, the inventors and applicants of the present application previously disclosed in Japanese Unexamined Patent Publication No. 2019-206935 (Patent Document 3) that a coil disposed along the stroke direction of the valve body The valve body moves in the valve closing direction through the cooperation of the spring and a plurality of leaf springs arranged in parallel at a predetermined interval to support the valve body and are provided at right angles to the stroke direction of the valve body. We have proposed an injector that maintains a valve closed state when de-energized while being energized.

This makes it possible to stabilize the operating state while suppressing the inclination of the valve body when it is displaced, making it easy to maintain the sealing performance when the valve is closed over a long period of time. However, although this method is effective in reducing uneven wear of the valve rubber while preventing the valve body from tilting, the impact load between the valve body and the valve seat increases significantly due to the high pressure of the supplied fuel. The problem of reduced durability of valve rubber caused by this cannot be adequately addressed.

Japanese Patent Application Publication No. 2010-096073 JP2020-037927A JP2019-206935A

The present invention aims to solve the above-mentioned problems, and aims to prevent excessive wear of the valve body of a gaseous fuel injector due to increased impact load between the valve body and the valve seat during valve closing operation. An object of the present invention is to prevent this problem and maintain the sealing performance of an on-off valve for a long period of time.

A gaseous fuel injector according to the present invention, which has been made to solve the above problems, includes a valve seat having a valve hole formed in the center thereof, and is disposed coaxially with the valve seat and is movable in the axial direction. A valve body is fixed to a movable iron core biased toward the valve seat and opens and closes the valve hole, and an on-off valve is provided. In an electromagnetically driven gaseous fuel injector in which the movable iron core is electromagnetically attracted by energizing the coil, the valve body is placed in an open state separated from the valve seat, and gaseous fuel is injected through the valve hole, The valve seat is formed such that an annular protrusion consisting of an inner annular protrusion and an outer annular protrusion that are formed double concentrically surrounds the open end of the valve hole so as to be able to come into contact with the valve body, and the annular protrusion is characterized in that the upper end edge of the inner annular protrusion and the upper end edge of the outer annular protrusion both contact the valve body in the valve closed state.

In this way, in an electromagnetically driven gaseous fuel injector, double annular protrusions consisting of an inner annular protrusion and an outer annular protrusion are formed concentrically in the part of the valve seat where the valve body contacts, thereby making it possible to open and close the valve. By increasing the contact area at the sealing part of the valve body, it is possible to ensure sealing performance while dispersing and buffering the shock associated with the valve closing operation during high-pressure fuel injection, etc., thereby preventing excessive contact between the valve body and the valve seat. By preventing the occurrence of wear, the sealing performance of the on-off valve can be maintained for a long period of time.

Further, in the annular projection, the inner annular projection is formed higher than the outer annular projection, and when the inner annular projection contacts the valve body before the outer annular projection during a valve closing operation, the inner annular projection contacts the valve body before the outer annular projection. The inner annular protrusion surrounding the hole ensures reliable contact with the valve body in the valve closed state, and when the valve is closed, the inner annular protrusion always comes into contact with the valve body first, and after a slight delay, the outer annular protrusion comes into contact with the valve body. Due to the structure that makes contact with the body, the impact when the valve is closed is dispersed in two stages, providing excellent impact dispersion and buffering effects.

Further, when the outer annular projection is formed with a plurality of communication grooves through which gaseous fuel can pass between the inner and outer sides of the outer annular projection in the valve closed state, the outer annular projection has contact with the valve body side. Since only the inner annular protrusion has an air-tightness maintaining function while exhibiting only the area increasing function, it becomes easy to realize precise control of the amount of fuel supplied by the injector.

Further, when the movable iron core is supported in a floating state by a disk-shaped leaf spring arranged perpendicular to the axial direction, the leaf spring may be supported in a floating state without a sliding part and moved linearly. This is advantageous in terms of durability and responsiveness, and the valve can be opened and closed in a stable posture by preventing the movable core and the valve body from tilting.

According to the present invention, excessive wear of the valve body caused by increased impact load between the valve body and the valve seat during valve closing operation is prevented, and the sealing performance of the open/close valve can be maintained for a long period of time. .

FIG. 1 is a partial vertical cross-sectional view showing the configuration of the front end side of a gaseous fuel injector according to an embodiment of the present invention. (a) A top view and (b) a perspective view showing a valve seat in the gaseous fuel injector of FIG. 1. FIG. 3 is an enlarged vertical cross-sectional view of the valve seat shown in FIG. 2. FIG. 2 is a partial vertical cross-sectional view showing the configuration of the tip side of a conventional gaseous fuel injector.

EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated with reference to drawings.

FIG. 1 is a vertical cross-sectional partial view showing the detailed structure of the tip side portion having technical features in a gaseous fuel injector 1 according to the present embodiment. This gaseous fuel injector 1 opens and closes by attracting a movable core by energizing and energizing an internal electromagnetic coil to supply gaseous fuel that has been reduced and adjusted to a predetermined pressure at the flow rate required by the engine. This is an electromagnetically driven injector that injects fuel with the valve open.

To explain in more detail, the gaseous fuel injector 1 includes a valve seat 40 having a valve hole 41 formed in the center and a valve body 50 for opening and closing the valve hole 41 inside the body 10 made of a cylindrical member. The valve body 50 is disposed coaxially with the valve seat 40 and is movable in the axial direction, and is biased toward the valve seat 40 by the coil spring 21 and It is fixed to the bottom side of a movable iron core 23 that is supported in a floating state by a disk-shaped leaf spring 22 arranged perpendicular to the direction. Incidentally, reference numeral 24 is a joint portion by screw fitting for integrally joining the movable core 23 and the valve body 50.

Then, by energizing and energizing the electromagnetic coil 25 disposed at the center of the fixed core 26, the movable core 26 is moved toward the fixed core 26, which is coaxial with the movable core 23 and located on the opposite side of the valve seat 40. 23 is electromagnetically attracted to the valve seat 40, the valve body 50 is brought into the valve open state separated from the valve closed position where it is in close contact with the valve seat 40 by the biasing force of the coil spring 21, and gaseous fuel is released through the valve hole 41. Make it spray.

In the present invention, a ring-shaped (doughnut-shaped) annular projection 60 serving as a seat surface is formed on the upper surface of the valve seat 40 so as to surround the opening end 42 of the valve hole 41. The valve rubber 51 of the valve body 50, which serves as a sealing surface, comes into close contact with the valve to bring the valve into a closed state. The upper end edge 71 of the inner annular projection 70 and the upper end edge 81 of the outer annular projection 80 are both in contact with the surface of the valve rubber 51 of the valve body 41 in the valve closed state. This is the most distinctive part of the invention.

In this way, by forming double annular protrusions concentrically at the portion of the valve seat 40 that contacts the valve body 50, the contact area at the sealing portion of the on-off valve 30 is expanded. This makes it possible to ensure sealing performance while dispersing and buffering shocks associated with valve closing operations during high-pressure fuel injection, etc., and excessive wear occurs on the valve rubber 51 of the valve body 50 that comes into contact with the valve seat 40. By preventing this, the sealing performance of the on-off valve 30 can be maintained for a long period of time.

FIG. 2(a) is a plan view of the valve seat 40, which is a characteristic part of the gaseous fuel injector 1, FIG. 2(b) is a perspective view (the lower part is omitted), and FIG. 40 is an enlarged longitudinal cross-sectional view of FIG.

In the valve seat 40, which is a cylindrical component, the annular projection 60 is formed such that the height T1 of the inner annular projection 70 is slightly higher than the height T2 of the outer annular projection 80. This is also an important feature of this embodiment.

In this way, by forming the height T1 of the inner annular projection 70 to be higher than the height T2 of the outer annular projection 80, the inner annular projection 70 is placed earlier than the outer annular projection 80 during the valve closing operation. It comes into contact with the valve rubber 51 of the valve body 50.

Therefore, in addition to ensuring that the inner annular protrusion 70 surrounding the valve hole 41 is in reliable contact with the valve rubber 51 in the valve closing state, the inner annular protrusion 70 always comes first during the valve closing operation. Since the structure is such that the outer annular protrusion 80 comes into contact with the valve rubber 51 after a slight delay, the impact during the valve closing operation is dispersed in two stages and provides excellent impact. Since it exhibits a buffering effect, the gaseous fuel injector 1 of this embodiment has excellent durability.

Further, in this embodiment, among the double annular projections 60 on the valve seat 40, the outer annular projection 80 is provided with a gaseous fuel by communicating between the inside and the outside surrounded by the annular shape. Another feature is that the four communication grooves 82 through which the water can pass are formed at equal intervals in the circumferential direction.

In this way, by providing the communication groove 82 that communicates the inside and outside surrounded by the doughnut-shaped outer annular projection 80 in the valve closed state, the outer annular projection 80 is brought into contact with the valve rubber 51. Since only the inner annular protrusion 70 has an air-tightness maintaining function while exhibiting only the area increasing function, precise control of the fuel supply amount in the gaseous fuel injector 1 can be easily realized.

As described above, with respect to gaseous fuel injectors, the present invention prevents excessive wear of the valve body caused by increased impact load between the valve body and the valve seat during valve closing operation, and seals the open/close valve. Performance can be maintained over a long period of time.

Reference Signs List 1 Gaseous fuel injector, 10 Body, 21 Coil spring, 22 Leaf spring, 23 Movable core, 24 Coupling portion, 25 Electromagnetic coil, 26 Fixed core, 30 Opening/closing valve, 40 Valve seat, 41 Valve hole, 42 Opening end, 50 Valve body, 51 Valve rubber, 60 Annular projection, 70 Inner annular projection, 71 Upper edge, 80 Outer annular projection, 81 Upper edge, 82 Communication groove

Claims (4)

A valve seat having a valve hole formed through the center thereof, and a movable iron core disposed coaxially with the valve seat, movable in the axial direction, and biased toward the valve seat by a coil spring, and fixed to a movable core that is biased toward the valve seat by a coil spring. Equipped with an on-off valve consisting of a valve body that opens and closes,
From the closed state in which the valve body is in close contact with the valve seat, the movable iron core is electromagnetically attracted by energizing the electromagnetic coil to change to the open state in which the valve body is separated from the valve seat, and the valve hole is closed. In an electromagnetically driven gas fuel injector that injects gaseous fuel through the
The valve seat is formed such that an annular protrusion consisting of an inner annular protrusion and an outer annular protrusion formed double concentrically surrounds the open end of the valve hole and can come into contact with the valve body,
The gaseous fuel injector is characterized in that the annular protrusion has an upper end edge of the inner annular protrusion and an upper end edge of the outer annular protrusion both in contact with the valve body in a valve closed state. The annular protrusion is characterized in that the inner annular protrusion is formed higher than the outer annular protrusion, and the inner annular protrusion contacts the valve body earlier than the outer annular protrusion during a valve closing operation. The gaseous fuel injector according to claim 1. 3. The gas according to claim 1 or 2, wherein the outer annular projection is formed with a plurality of communication grooves through which gaseous fuel can pass between the inside and outside of the outer annular projection in the valve closed state. Fuel injector. 3. The gaseous fuel injector according to claim 1, wherein the movable iron core is supported in a floating state by a disc-shaped leaf spring arranged perpendicular to the axial direction.

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