Support structure for fuel injection valve

Abstract

The present invention provides a fuel injection valve support structure which has a simple structure and which makes it possible to prevent a fuel injection valve from rotating about the axis of a valve housing thereof, without providing a special rotation-stopping piece to an elastic support member. In this support structure, a notch (19) which receives a valve housing (1) is provided to a base plate (15) of an elastic support member (S), and a rotation-preventing protrusion (20) which engages with the notch (19) and prevents rotation of a fuel injection valve (I) about the axis (A) of the valve housing (1) is formed in a synthetic resin formation part (6) that covers the valve housing (1), with a coupler (14) protruding to one side.

Description

[Technical field]

[0001] The present invention relates to a support structure for a fuel injection valve used in an engine, and in particular to an improvement in the support structure for a fuel injection valve in which a fuel nozzle portion of a valve housing is fitted into an injection valve mounting hole of the engine, and a fuel supply cap of a fuel distribution pipe supported by the engine is fitted into the fuel inlet portion of the valve housing, and an elastic support member is interposed between the valve housing and the fuel supply cap for urging the valve housing toward the injection valve mounting hole, thereby elastically clamping the fuel injection valve between the engine and the fuel supply cap to prevent it from moving axially. [Background technology]

[0002] Such a support structure for a fuel injection valve is already known, as disclosed in Patent Document 1 below. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-174227 A Summary of the Invention [Problem to be solved by the invention]

[0004] In such a support structure for a fuel injection valve, if the fuel injection valve rotates even slightly around the axis of the valve housing due to vibration during engine operation, the direction of the fuel injected from the fuel nozzle tube changes, adversely affecting the fuel combustion state in the engine. Therefore, in the support structure for a fuel injection valve described in the above Patent Document 1, a pair of anti-rotation pieces that extend from both side ends of the base plate of the elastic support member and bend toward the fuel nozzle tube side are connected to the base plate, and these anti-rotation pieces are abutted against flat surfaces formed on both sides of the valve housing to prevent the above-mentioned rotation of the fuel injection valve.

[0005] However, in the above support structure, providing a pair of anti-rotation pieces connected to the base plate complicates the shape of the elastic support member, increasing the number of processing steps and reducing the material yield, which has the disadvantage of increasing the cost of the support structure.

[0006] The present invention has been made in consideration of such circumstances, and aims to provide a simple support structure for a fuel injection valve that makes it possible to prevent rotation of the fuel injection valve around the axis of the valve housing without the need for a special anti-rotation piece on the elastic support member. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides a valve housing having a fuel nozzle cylindrical portion fitted into an injection valve mounting hole of an engine, a fuel supply cap of a fuel distribution pipe supported by the engine fitted into a fuel inlet cylindrical portion of the valve housing, and an elastic support member is interposed between the valve housing and the fuel supply cap, which biases the valve housing toward the injection valve mounting hole and is connected to the fuel supply cap while preventing the valve housing from rotating about its axis, The elastic support member 、 The valve housing a base plate abutting against a base surface facing the fuel supply cap; Extending from one end of the base plate A pair of valves are formed, each of which has a tip end overlapping a tip end of the base plate while straddling the valve housing. an elastic piece that is in elastic contact with the fuel supply cap; 、 The base plate is provided with a notch for receiving the valve housing. In a support structure for a fuel injection valve, The valve housing is covered with a synthetic resin molded portion while a power supply coupler protrudes to one side, the base surface is formed by a rear end surface of the synthetic resin molding portion, The synthetic resin molding portion is The pair of elastic pieces protrude from the base surface between the valve housing and the coupler, and engage with the notch of the base plate and the tip ends of the pair of elastic pieces, thereby providing a spring for the fuel supply cap. The valve housing Episode Anti-rotation protrusion to prevent rotation Integrate The present invention is characterized by being equipped with:

[0009] In addition, the present invention In the past, The anti-rotation projection is disposed between the valve housing and the coupler. Good . Effect of the Invention

[0010] This issue Clearly According to this, a notch for receiving the valve housing is provided in the base plate of the elastic support member, and a rotation prevention protrusion that engages with this notch is formed in the synthetic resin molded portion that covers the valve housing, thereby preventing rotation of the fuel injection valve about the axis of the valve housing and always stabilizing the direction of the fuel injected from the cylindrical fuel nozzle portion. Therefore, it is not necessary to provide a pair of rotation prevention pieces that would complicate the shape of the elastic support member. Meanwhile, the rotation prevention protrusion can be molded integrally with the coupler in the synthetic resin molded portion that covers the valve housing. As a result, the number of machining operations for each component is not increased, the material yield is improved, and the cost of the support structure for the fuel injection valve can be reduced.

[0011] Also , bullets The tip ends of a pair of elastic pieces of the elastic support member that straddle the valve housing are overlapped with the tip end of the base plate, and the anti-rotation protrusion engages between the tip ends of the pair of elastic pieces, thereby strengthening the engagement force between the elastic support member and the anti-rotation protrusion, thereby reliably preventing rotation of the fuel injection valve.

[0012] moreover ,before Since the protrusion is positioned between the valve housing and the coupler, when the elastic support member is inserted between the fuel injection valve and the fuel supply pipe, it can be inserted from the opposite side to the coupler, allowing the elastic support member to be easily engaged with the anti-rotation protrusion without interference from the coupler, resulting in good assembly ease. [Brief description of the drawings]

[0013] [Figure 1] 1 is a partial vertical sectional front view showing a support structure for a fuel injection valve in a multi-cylinder engine according to an embodiment of the present invention; [Diagram 2] Enlarged cross-sectional view of line 2-2 in Figure 1. [Diagram 3] Cross-sectional view taken along line 3-3 in Figure 2. [Figure 4] FIG. 4 is a perspective view of the elastic support member shown in each figure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] An embodiment of the present invention will be described with reference to the accompanying drawings.

[0015] 1 and 2, a cylinder head Eh of a multi-cylinder engine E is fitted with a plurality of fuel injection valves I capable of injecting fuel into the combustion chambers Ec of a plurality of cylinders, and a fuel distribution pipe D for distributing fuel to these fuel injection valves I. An elastic support structure equipped with an elastic support member S is used to hold each fuel injection valve I in a fixed position. The structure will be described in detail below.

[0016] Each fuel injection valve I has at its center a cylindrical valve housing 1. The front end of this valve housing 1 is a fuel nozzle section 2, the rear end is a fuel introduction section 4, and the middle section is an electromagnetic coil section 3. When an electric current is applied to the electromagnetic coil section 3, a valve in the fuel nozzle section 2 opens, and the fuel introduction section 4 injects the fuel introduced from the fuel distribution pipe D into the corresponding combustion chamber Ec.

[0017] The electromagnetic coil section 3 is covered with a synthetic resin molded section 6, and a coupler 14 for supplying power to the electromagnetic coil section 3 is integrally provided on one side of the synthetic resin molded section 6 in a protruding manner.

[0018] An annular seal / cushion member 8 is attached to the outer periphery of the fuel nozzle cylindrical portion 2, in close contact with the front end face of the synthetic resin molded portion 6. An O-ring 9 is attached to the seal groove 4a on the outer periphery of the fuel inlet cylindrical portion 4.

[0019] Further, the rear end surface of the synthetic resin molded portion 6 facing the fuel introduction tube portion 4 side is made into a flat base surface 5 .

[0020] On the other hand, the cylinder head Eh is provided with an injection valve mounting hole 10 whose inner end opens into the ceiling surface of each combustion chamber Ec, and an annular recess 11 surrounding the outer opening end of the injection valve mounting hole 10, and the fuel nozzle tube portion 2 of the fuel injection valve I is fitted into the injection valve mounting hole 10, and a seal / cushion member 8 is housed in the recess 11.

[0021] The fuel distribution pipe D is arranged along the direction in which the cylinders of the engine E are arranged, and fuel is pumped from one end of the fuel distribution pipe D by a fuel pump (not shown). On one side of the fuel distribution pipe D, a plurality of fuel supply caps Da are protrudingly arranged coaxially with the plurality of fuel injection valves I fitted into the plurality of injection valve mounting holes 10, and each of these fuel supply caps Da is fitted onto the outer periphery of the fuel introduction tube portion 4 of the corresponding fuel injection valve I. At this time, the O-ring 9 is in close contact with the inner periphery of the fuel supply cap Da. On the outer side of each fuel supply cap Da, a flat stopper surface 7 parallel to the axis A of the valve housing 1 is formed. A bracket Db is fixed to the base of each fuel supply cap Da, and this bracket Db is fixed by a bolt 13 to a support 12 erected on the upper surface of the cylinder head Eh.

[0022] As shown in FIGS. 2 to 4, the elastic support member S is made by pressing a steel plate, and is composed of a base plate 15, an elastic piece 16, and a positioning piece .

[0023] The base plate 15 is placed on the base surface 5, and has a U-shaped notch 19 in its center that can receive the valve housing 1. A pair of elastic pieces 16 that elastically come into contact with the front end surface of the fuel supply cap Da are molded so as to be connected integrally to one end of the base plate 15 opposite the U-shaped notch 19. The elastic pieces 16 are arranged with a gap between them that can receive the fuel introduction tube portion 4 of the fuel injection valve I.

[0024] Each elastic piece 16 consists of a first elastic portion 16a bent upward from one end of the base plate 15 in a horizontal U-shape, and a second elastic portion 16b which curves upward from the first elastic portion 16a toward the other end and whose tip portion 16ba comes into resilient contact with the upper surface of the base plate 15 so as to be able to slide, and the radius of curvature R2 of the second elastic portion 16b is set to be sufficiently larger than the radius of curvature R1 of the first elastic portion 16a (see Figure 4).

[0025] In the free state of elastic piece 16, distance L1 (see FIG. 4) from the apex of second elastic portion 16b to the bottom surface of base plate 15 is set to be greater than distance L2 (see FIG. 2) from base surface 5 to the front end surface of fuel supply cap Da. Therefore, when base plate 15 and elastic piece 16 are inserted between base surface 5 and fuel supply cap Da, elastic piece 16 comes into elastic contact with the front end surface of fuel supply cap Da while bending first and second elastic portions 16a, 16b. Tip portion 16ba of second elastic portion 16b can slide on the top surface of base plate 15 when first and second elastic portions 16a, 16b are bent, and has an upwardly curved shape to make the sliding smooth.

[0026] A positioning piece 18 that stands vertically upward from between a pair of elastic pieces 16 is integrally attached to one end of the base plate 15, and this positioning piece 18 is capable of abutting against the stopper surface 7 of the fuel supply cap Da.

[0027] In addition, a rotation prevention protrusion 20 is integrally formed with the synthetic resin molded portion 6, protruding from the base surface 5 between the valve housing 1 and the coupler 14, and this rotation prevention protrusion 20 is adapted to engage with the notch 19 in the base plate 15 and between the tip ends 16ba of the pair of elastic pieces 16 which come into resilient contact with the base plate 15 when the elastic support member S is positioned in a fixed position between the synthetic resin molded portion 6 and the fuel supply cap Da.

[0028] Next, the operation of this embodiment will be described.

[0029] When mounting the fuel injection valve I on the engine E, first, the fuel supply cap Da of the fuel distribution pipe D is fitted onto the fuel inlet tube portion 4 of the fuel injection valve I. Next, starting from the opening of the U-shaped notch 19 of the base plate 15, the elastic support member S is inserted between the base surface 5 of the fuel injection valve I and the fuel supply cap Da from the outer side of the fuel injection valve I opposite the coupler 14, and while receiving the valve housing 1 between the notch 19 of the base plate 15 and the pair of elastic pieces 16, the positioning piece 18 is abutted against the stopper surface 7 of the fuel supply cap Da.

[0030] This abutment prevents the elastic support member S from rotating relative to the fuel supply cap Da.

[0031] At the same time as the above-mentioned abutment, the anti-rotation protrusion 20 of the synthetic resin molded portion 6 engages between the notch 19 of the base plate 15 of the elastic support member S and the pair of elastic pieces 16, thereby preventing the fuel injection valve I from rotating around the axis A of the valve housing 1 relative to the fuel supply cap Da.

[0032] Thereafter, the fuel nozzle tube portion 2 of the fuel injection valve I is inserted into the injection valve mounting hole 10 of the cylinder head Eh, and the seal / cushion member 8 in close contact with the front end face of the synthetic resin molded portion 6 is placed in the recess 11. Then, while a compressive load is being applied to the elastic support member S, the bracket Db is fixed to the support pillar 12 of the cylinder head Eh with the bolt 13.

[0033] At this time, the pair of elastic pieces 16 elastically press the front end face of the fuel supply cap Da on a plane including the axis A of the valve housing 1 with the apex of the second elastic part 16b while bending the first and second elastic parts 16a, 16b, and the pressing reaction force presses the base plate 15 against the base surface 5, so that the fuel injection valve I is elastically sandwiched between the cylinder head Eh and the fuel supply cap Da via the elastic support member S and the seal / cushion member 8. Moreover, since the pressing reaction force of the elastic pieces 16 against the fuel supply cap Da acts on the fuel injection valve I along its central axis A, the support can be stabilized without tilting the fuel injection valve I.

[0034] Thus, the fuel injection valve I mounted on the engine E is prevented from rotating about the axis A of the valve housing 1 relative to the fuel supply cap Da via the elastic support member S, thereby ensuring that the direction of the fuel injected from the fuel nozzle portion 2 is always stable.

[0035] Incidentally, the rotation prevention of the fuel injection valve I relative to the elastic support member S about the axis A of the valve housing 1 is achieved by engaging the rotation prevention protrusion 20 of the synthetic resin molded part 6 between the notch 19 of the base plate 15 originally provided on the elastic support member S and the pair of elastic pieces 16, as described above, so there is no need to provide the elastic support member S with a special rotation prevention piece as in the past, and the shape of the elastic support member S can be simplified. Also, the rotation prevention protrusion 20 is integrally molded together with the coupler 14 on the synthetic resin molded part 6 that covers the valve housing 1 so as to encase the electromagnetic coil part 3, so that the number of machining operations for each part is not increased, and the material yield is improved, thereby reducing the cost of the support structure for the fuel injection valve I.

[0036] In the present invention, for example, the height of the anti-rotation protrusion 20 may be set equal to the thickness of the base plate 15, or the tip portions 16ba of the pair of elastic pieces 16 may terminate just before the anti-rotation protrusion 20 so that only the notches 19 of the base plate 15 engage with the anti-rotation protrusion 20. However, as described above, if both the base plate 15 and the elastic pieces 16 are engaged with the anti-rotation protrusion 20, the engagement force between the elastic support member S and the anti-rotation protrusion 20 is strengthened, and rotation of the fuel injection valve I can be reliably prevented.

[0037] Furthermore, since the anti-rotation protrusion 20 is positioned between the valve housing 1 and the coupler 14, when the elastic support member S is inserted between the fuel injection valve I and the fuel supply cap Da, by inserting it from the opposite side to the coupler 14, the elastic support member S can be easily engaged with the anti-rotation protrusion 20 without being interfered with by the coupler 14, resulting in good assembly ease.

[0038] Furthermore, each elastic piece 16 is composed of a first elastic portion 16a with a small radius of curvature R1 that is connected to one end of the base plate 15, and a second elastic portion 16b with a large radius of curvature R2 that extends from the first elastic portion 16a and has a tip portion 16ba that slidably abuts against the upper surface of the other end of the base plate 15. Therefore, the second elastic portion 16b is supported at both ends by the base plate 15 via its tip portion 16ba and the first elastic portion 16a. Therefore, even if the first elastic portion 16a undergoes plastic deformation (generally, a portion that is bent with a small radius of curvature is prone to plastic deformation), the elastic force of the second elastic portion 16b can maintain the biasing function of each elastic piece 16 against the fuel supply cap Da. Furthermore, by making the radius of curvature R2 of the second elastic portion 16b larger than the radius of curvature R1 of the first elastic portion 16a, the height of each elastic piece 16 can be kept as low as possible, making it easy to attach the elastic support member S to the narrow space between the base surface 5 and the fuel supply cap Da.

[0039] Although the embodiment of the present invention has been described above, the present invention is not limited thereto, and various design modifications are possible without departing from the gist of the present invention. For example, the present invention is also applicable to a structure for attaching a fuel injection valve I to an intake system of an engine. [Explanation of symbols]

[0040] A: Axis of valve housing D...Fuel distribution pipe Da...Fuel supply cap E····Engine I. Electromagnetic fuel injection valve S...Elastic support member 2. Fuel nozzle cylinder 3. Electromagnetic coil section 4...Fuel introduction cylinder part 5...Base surface 6. Synthetic resin molding part 7 Stopper surface 10...Injection valve mounting hole 14... Coupler 15 Base plate 16 Elastic piece 16ba Tip of elastic piece 18 Positioning piece 19 Notch 20 Anti-rotation protrusion

Claims

1. A fuel nozzle cylindrical portion (2) of a valve housing (1) is fitted into an injection valve mounting hole (10) of an engine (E), a fuel supply cap (Da) of a fuel distribution pipe (D) supported by an engine (E) is fitted into a fuel inlet cylindrical portion (4) of the valve housing (1), and an elastic support member (S) is interposed between the valve housing (1) and the fuel supply cap (Da) to bias the valve housing (1) toward the injection valve mounting hole (10) while connecting the fuel supply cap (Da) to the valve housing (1) so as to disable rotation of the valve housing (1) about an axis (A), The elastic support member (S) is a base plate (15) that abuts against a base surface (5) of the valve housing (1) that faces the fuel supply cap (Da); a pair of elastic pieces (16) extending from one end of the base plate (15), straddling the valve housing (1) and overlapping a tip end portion (16ba) of the base plate (15), and elastically contacting the fuel supply cap (Da); In the support structure for a fuel injection valve, a notch (19) for receiving the valve housing (1) is provided in the base plate (15), The valve housing (1) is covered with a synthetic resin molded portion (6) with a power supply coupler (14) protruding to one side, The base surface (5) is formed by a rear end surface of the synthetic resin molded portion (6), The synthetic resin molded portion (6) is a pair of elastic pieces (16) each having a pair of recesses (19) formed in the base plate (15) and a recess (16b) between the pair of recesses (19) and (20) of the valve housing (1) and the coupler (14), the pair of recesses (19) being spaced apart from each other by a recess (16b) and a recess (16c) between the pair of recesses (19) and (20).

2. 2. The support structure for a fuel injection valve according to claim 1, A support structure for a fuel injection valve, characterized in that the anti-rotation projection (20) is disposed between the valve housing (1) and the coupler (14).

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