Support structure for fuel injection valve

Abstract

In the support structure of the fuel injection valve (I), a snap projection (21) which is snap-fitted to the outer peripheral surface of the fuel introduction cylinder portion (4) received in the notch (19) of the base plate (15) is formed on the inner side surface of the notch (19). In the state where the fuel injection valve (I) is mounted to the engine (E), the contact frictional force of the elastic sheet (16) with respect to the base plate (15) increases due to the increase in the elastic rebound force of the elastic sheet (16), so that the snap-fitting force of the snap projection (21) with respect to the fuel introduction cylinder portion (4) is automatically increased.

Description

Technical Field

[0001] This invention relates to a support structure for a fuel injection valve used in an engine, and particularly to an improvement in the support structure of a fuel injection valve in which the fuel nozzle portion of the valve housing is fitted into the injection valve mounting hole of the engine, and a fuel supply cap for a fuel distribution pipe supported by the engine is fitted into the fuel inlet portion of the valve housing. An elastic support member is sandwiched between the valve housing and the fuel supply cap, applying force to 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 axial movement. Background Technology

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

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2013-174227

[0006] Patent Document 2: Japanese Patent Publication No. 2002-516957 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] After the fuel injection valve is manufactured, it is transported to the engine assembly line. The elastic support component is pre-installed in a fixed position on the fuel injection valve, but during this transport process, it must be ensured that the elastic support component does not detach or shift from the fuel injection valve. To prevent this detachment or shifting, in the fuel injection valve support structure described in Patent Document 1, a pair of clamping plates extending curved from one end towards the fuel nozzle cylinder are continuously provided on the base plate of the elastic support component. These clamping plates elastically clamp the flat sides of the valve housing. While this support structure allows for easy installation of the elastic support component onto the fuel injection valve, the continuous provision of a pair of clamping plates on the base plate has the following disadvantages: it complicates the structure of the elastic support component, increases processing steps, reduces the yield of raw materials, and increases the cost of the support structure.

[0009] On the other hand, in the fuel injection valve support structure described in Patent Document 2, the elastic support member is installed on the fuel injection valve via a snap-fit ​​structure. However, when the snap-fit ​​force is sufficiently increased, its installability deteriorates. Therefore, when the snap-fit ​​force is set relatively weak to consider its installability, the elastic support member may detach from the fuel injection valve due to engine vibration when the fuel injection valve is installed on the engine.

[0010] The present invention was made in view of the following circumstances, and its object is to provide a support structure for a fuel injection valve. In order to simplify the structure of the elastic support member and to ensure good installation of the elastic support member to the fuel injection valve, it adopts a snap-fit ​​structure, and can automatically enhance the snap-fit ​​force when the fuel injection valve is installed in the engine to prevent the elastic support member from detaching from the fuel injection valve.

[0011] Methods for solving problems

[0012] The first feature of the present invention is a support structure for a fuel injection valve, wherein the fuel nozzle portion of the valve housing is fitted into the injection valve mounting hole of an engine, and a fuel supply cap for a fuel distribution pipe supported by the engine is fitted onto the fuel inlet portion of the valve housing. An elastic support member is sandwiched between the valve housing and the fuel supply cap, applying force to the valve housing toward the injection valve mounting hole. This elastic support member comprises: a base plate having a U-shaped notch for receiving the outer periphery of the fuel inlet portion, opposite to the fuel supply cap on the valve housing. The base surface overlaps; and an elastic sheet extends from one end of the base plate and elastically contacts the fuel supply cap at its middle portion and elastically contacts the base plate at its end portion, wherein a snap-fit ​​protrusion is formed on the inner side of the notch to snap into the outer peripheral surface of the fuel inlet cylinder received in the notch, and when the fuel injection valve is installed in the engine, as the flexural rebound force of the elastic sheet increases, the contact friction force of the elastic sheet relative to the base plate increases, thereby increasing the snap-fit ​​force of the snap-fit ​​protrusion relative to the fuel inlet cylinder.

[0013] In addition to the first feature, the second feature of the present invention is that a first cut is provided in the middle of the two outer sides of the base plate.

[0014] Furthermore, in addition to the first or second feature, the third feature of the present invention is that a second cut is provided on the base plate adjacent to the root of the elastic sheet.

[0015] Invention Effects

[0016] According to a first feature of the present invention, when a snap-fit ​​structure is employed, even if the snap-fit ​​force is set with priority given to the installability of the elastic support member to the fuel injection valve, when the fuel injection valve is installed in the engine, the contact friction between the elastic sheet and the base plate increases due to the flexural rebound force of the elastic sheet. This increases the resistance to the expansion of the notch on the base plate, thereby increasing the resistance to the snap-fit ​​protrusion disengaging from the fuel inlet cylinder. Thus, it is possible to prevent the elastic support member from detaching from the fuel injection valve. Furthermore, by employing a snap-fit ​​structure, the structure of the elastic support member can be simplified, resulting in cost reduction.

[0017] According to a second feature of the present invention, by providing a first cut in the middle of the two outer sides of the base plate, the spring constant of the base plate can be reduced without changing the contact area between the end of the elastic piece and the base plate or the height of the snap-fit ​​protrusion. As a result, the snap-fit ​​force can be reduced and adjusted, thereby improving the installability of the elastic support component to the fuel injection valve.

[0018] According to a third feature of the present invention, by providing a second cut adjacent to the root of the elastic sheet on the base plate, similarly to the above, the spring constant of the base plate can be reduced without changing the contact area between the end of the elastic sheet and the base plate or the height of the snap-fit ​​protrusion. As a result, the snap-fit ​​force can be reduced and adjusted, thereby improving the installability of the elastic support component to the fuel injection valve. Attached Figure Description

[0019] Figure 1 This is a partial longitudinal sectional front view showing the support structure of the fuel injection valve in a multi-cylinder engine according to an embodiment of the present invention.

[0020] Figure 2 yes Figure 1 Enlarged sectional view along line 2-2.

[0021] Figure 3 yes Figure 2 3-3 line section view.

[0022] Figure 4 These are individual three-dimensional views of the elastic support components in each figure. Detailed Implementation

[0023] The embodiments of the present invention will be described with reference to the accompanying drawings.

[0024] First of all, Figure 1 and Figure 2 In this multi-cylinder engine E, multiple fuel injection valves I capable of injecting fuel into the combustion chambers Ec of multiple cylinders are mounted on the cylinder head Eh, along with a fuel distribution pipe D that distributes fuel to these fuel injection valves I. Furthermore, in order to hold each fuel injection valve I in a fixed position, an elastic support structure with an elastic support member S is used. This structure will be described in detail below.

[0025] Each fuel injection valve I has a cylindrical valve body 1 at its center. The front end of the valve body 1 becomes the fuel nozzle cylinder 2, the rear end becomes the fuel inlet cylinder 4, and the middle part becomes the electromagnetic coil 3. When the electromagnetic coil 3 is energized, the valve inside the fuel nozzle cylinder 2 is opened, and the fuel inlet cylinder 4 injects the fuel introduced from the fuel distribution pipe D into the corresponding combustion chamber Ec.

[0026] In addition, the electromagnetic coil section 3 is covered by the synthetic resin molding 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 molding section 6.

[0027] An annular sealing and buffering member 8 is installed on the outer periphery of the fuel nozzle cylinder 2, which is in close contact with the front end face of the synthetic resin molding part 6. In addition, an O-ring 9 is installed in the sealing groove 4a on the outer periphery of the fuel inlet cylinder 4.

[0028] In addition, the rear end face of the synthetic resin molding part 6 facing the fuel inlet cylinder part 4 is a flat base surface 5.

[0029] On the other hand, the cylinder head Eh is provided with an injection valve mounting hole 10 with its inner end opening to the top surface of each combustion chamber Ec and an annular recess 11 surrounding its outer opening end. The fuel nozzle cylinder 2 of the fuel injection valve I is embedded in the injection valve mounting hole 10, and a sealing and buffering component 8 is housed in the recess 11.

[0030] Furthermore, the fuel distribution pipe D is arranged along the arrangement direction of the multiple cylinders of the engine E, and fuel is pumped from one end by a fuel pump (not shown). Multiple fuel supply caps Da are protruding from one side of the fuel distribution pipe D, arranged coaxially with the aforementioned multiple fuel injection valves I. These fuel supply caps Da are respectively fitted into the outer periphery of the fuel inlet cylinder 4 of the corresponding fuel injection valve I. At this time, the aforementioned O-ring 9 is in close contact with the inner circumferential surface of the fuel supply cap Da.

[0031] A flat stop surface 7 parallel to the axis A of the valve housing 1 is formed on the outer surface of each fuel supply cover Da. A bracket Db is fixedly installed at the base of each fuel supply cover Da, and the bracket Db is fixed to a support column 12 erected on the upper surface of the cylinder head Eh by bolts 13.

[0032] like Figures 2 to 4 As shown, the above-mentioned elastic support component S is made by stamping steel plate and consists of base plate 15, elastic sheet 16 and positioning sheet 18.

[0033] The base plate 15 overlaps with the base surface 5, and a U-shaped notch 19 is provided in its center to accommodate the fuel inlet cylinder 4. The width of the notch 19 is set to be slightly larger than the outer diameter of the fuel inlet cylinder 4.

[0034] A pair of elastic pieces 16 are integrally and continuously provided at one end of the base plate 15 opposite to the notch 19, and are in elastic contact with the front end face of the fuel supply cover Da. The two elastic pieces 16 are arranged such that there is a gap between them that can accommodate the valve housing 1.

[0035] Each elastic sheet 16 is composed of a first elastic portion 16a and a second elastic portion 16b. The first elastic portion 16a bends upward from one end of the base plate 15 into a transverse U-shape. The second elastic portion 16b bends upward from the first elastic portion 16a and extends toward the other end, with its end portion 16ba slidably elastically contacting the upper surface of the base plate 15. 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 reference). Figure 4 ).

[0036] Furthermore, in the free state of the elastic sheet 16, the distance L1 from the apex of the second elastic part 16b to the lower surface of the base plate 15 (refer to...) Figure 4 The distance L2 from the base surface 5 to the front end surface of the fuel supply cover Da is set to (refer to...). Figure 2 Therefore, when the base plate 15 and the elastic sheet 16 are inserted between the base surface 5 and the fuel supply cover Da, the elastic sheet 16 causes the first and second elastic portions 16a and 16b to flex and elastically contact the front end face of the fuel supply cover Da. When the first and second elastic portions 16a and 16b flex, the end portion 16ba of the second elastic portion 16b can slide on the upper surface of the base plate 15, and in order to make its sliding smooth, it becomes an upwardly curved shape.

[0037] A positioning piece 18 is integrally and continuously provided at one end of the base plate 15, which rises vertically upward from between a pair of elastic pieces 16. The positioning piece 18 can abut against the stop surface 7 of the fuel supply cover Da.

[0038] On the two inner sides of the base plate 15 adjacent to the U-shaped notch 19, there is a pair of snap-fit ​​protrusions 21 that can snap into the outer peripheral surface of the fuel inlet cylinder 4 housed in the notch 19. That is, the spacing between the pair of snap-fit ​​protrusions 21 is set to be narrower than the outer diameter of the fuel inlet cylinder 4. During the process of housing the fuel inlet cylinder 4 in the notch 19, the base plate 15 flexes in the opening direction of the notch 19 and rests on the diameter portion of the fuel inlet cylinder 4. When passing through the diameter portion, the elastic restoring force of the base plate 15 closes the notch 19 to its original position. Thus, the snap-fit ​​protrusions 21 engage with the back side of the fuel inlet cylinder 4, and the engaging force prevents the elastic support member S from disengaging from the fuel inlet cylinder 4.

[0039] In addition, a pair of first cutouts 23 are provided in the middle of the two outer sides of the base plate 15. Furthermore, a pair of second cutouts 24 are provided on the base plate 15 adjacent to the roots of the two elastic pieces 16.

[0040] In addition, an anti-rotation protrusion 20 protruding from the base surface 5 between the valve housing 1 and the coupler 14 is integrally formed on the aforementioned synthetic resin molding part 6. When the elastic support member S is inserted into the fixed position between the base surface 5 and the fuel supply cover Da, the anti-rotation protrusion 20 engages between the notch 19 of the base plate 15 and the end portions 16ba of a pair of elastic sheets 16 that are in elastic contact with the base plate 15.

[0041] Next, the function of this implementation method will be explained.

[0042] First, when the manufactured fuel injection valve I is being transported to the engine assembly line, the elastic support component S is pre-installed on the fuel inlet cylinder 4 of the fuel injection valve I as described below.

[0043] That is, with the opening of the U-shaped notch 19 of the base plate 15 as the front, the elastic support member S is pressed in from the outside of the fuel injection valve I on the opposite side of the coupler 14 so that the fuel inlet cylinder 4 is housed in the notch 19 and between the two elastic plates 16.

[0044] Furthermore, because the spacing between the pair of snap-fit ​​protrusions 21 on the two inner sides of the notch 19 is set to be narrower than the outer diameter of the fuel inlet cylinder 4, the snap-fit ​​protrusions 21 cause the base plate 15 to flex and rest on the diameter portion of the fuel inlet cylinder 4 in the direction of the opening of the notch 19. Then, when passing through the diameter portion, the elastic restoring force of the base plate 15 closes the notch 19 to its original position. Thus, the snap-fit ​​protrusions 21 snap into the back side of the fuel inlet cylinder 4. This snap-fit ​​force can hold the elastic support member S in the fuel inlet cylinder 4, and during the delivery process, it can prevent the elastic support member S from disengaging or shifting from the fuel injection valve I.

[0045] Thus, by employing a snap-fit ​​structure in the installation of the elastic support component S onto the fuel injection valve I, good installation is achieved, and the structure of the elastic support component S is simplified.

[0046] Furthermore, while the aforementioned snap-fit ​​engages, the anti-rotation protrusion 20 of the synthetic resin molded part 6 engages between the notch 19 of the base plate 15 of the elastic support member S and a pair of elastic sheets 16. Thus, the fuel injection valve I and the elastic support member S are connected to each other so that they cannot rotate about the axis A of the valve housing 1.

[0047] When the fuel injection valve I with the elastic support member S installed is moved into the engine assembly line, the fuel supply cap Da of the fuel distribution pipe D is fitted into the fuel inlet cylinder 4 of the fuel injection valve I, and the positioning piece 18 of the elastic support member S abuts against the stop surface 7 of the fuel supply cap Da. Due to this abutment, the elastic support member S cannot rotate relative to the fuel supply cap Da. In addition, the anti-rotation protrusion 20 of the synthetic resin molding part 6 has engaged between the notch 19 of the base plate 15 of the elastic support member S and a pair of elastic pieces 16, thus preventing the rotation of the fuel injection valve I relative to the fuel supply cap Da about the axis A of the valve housing 1.

[0048] Next, the fuel nozzle cylinder 2 of the aforementioned fuel injection valve I is inserted into the injection valve mounting hole 10 of the cylinder head Eh, and the sealing and buffering component 8, which is in close contact with the front end face of the synthetic resin molding part 6, is housed in the recess 11. Then, while applying a compressive load to the elastic support component S, the bracket Db is fixed to the support column 12 of the cylinder head Eh with bolts 13.

[0049] At this time, a pair of elastic plates 16 cause the first and second elastic portions 16a and 16b to flex and elastically press the front end face of the fuel supply cover Da on the plane containing the axis A of the valve housing 1 through the vertex of the second elastic portion 16b. Furthermore, the flexural rebound force of the elastic plates 16 presses the base plate 15 against the base surface 5, thus the fuel injection valve I is elastically clamped between the cylinder head Eh and the fuel supply cover Da via the elastic support member S and the sealing and buffering member 8. Moreover, the pressing reaction force of the elastic plates 16 on the fuel supply cover Da acts on the fuel injection valve I along its central axis A, thus preventing the fuel injection valve I from tilting and ensuring stable support.

[0050] Furthermore, due to the flexural rebound force of the elastic sheet 16, the contact friction force between the elastic sheet 16 and the base plate 15 increases, that is, the friction force between the end of the elastic sheet 16 and the base plate 15 increases, which increases the resistance to the expansion of the notch 19 on the base plate 15. This means an increase in the resistance to the snap-fit ​​protrusion 21 disengaging from the fuel inlet cylinder 4, that is, an increase in the snap-fit ​​force. As a result, it is possible to prevent the elastic support component S from falling off the fuel injection valve I due to vibrations of the engine E, etc.

[0051] This achieves the following effects: the snap-fit ​​force from the snap-fit ​​protrusion 21 can be appropriately set with priority given to the installability of the elastic support member S to the fuel injection valve I; and the snap-fit ​​force can be increased when the fuel injection valve I and the fuel supply cap Da are installed together on the engine E. Moreover, by adopting a snap-fit ​​structure, it is not necessary to continuously provide a pair of clamping pieces as described in Patent Document 1 on the base plate 15 of the elastic support member S, thereby simplifying the structure of the elastic support member S and reducing costs.

[0052] In addition, as a method to reduce the locking force of the latch, a first cutout 23 is provided in the middle of the two outer sides of the base plate 15. As a result, the spring constant of the base plate 15 can be reduced without changing the contact area between the end of the elastic piece 16 and the base plate 15 or the height of the latch protrusion 21, thereby appropriately reducing the locking force of the latch.

[0053] Alternatively, as another method, a second cutout 24 adjacent to the root of the elastic piece 16 is provided on the base plate 15. This, similar to the method described above, moderately reduces the latching force. Furthermore, if both methods are used simultaneously, the latching force can be further reduced.

[0054] Furthermore, via the elastic support member S, the rotation of the fuel injection valve I mounted on the engine E relative to the fuel supply cover Da around the axis A of the valve housing 1 is prevented, thereby ensuring that the orientation of the injected fuel from the fuel nozzle cylinder 2 remains stable.

[0055] Furthermore, the anti-rotation of the fuel injection valve I relative to the axis A of the elastic support member S around the valve housing 1 is achieved by engaging the anti-rotation protrusion 20 of the synthetic resin molding portion 6 between the notch 19 of the base plate 15 originally provided in the elastic support member S and a pair of elastic sheets 16, thus avoiding the complication of the elastic support member S. In addition, the anti-rotation protrusion 20 and the coupler 14 are integrally molded together in the synthetic resin molding portion 6 that covers the valve housing 1 in a manner that embeds the electromagnetic coil portion 3, thus not increasing the number of parts to be processed and avoiding cost increases.

[0056] Furthermore, since the aforementioned anti-rotation protrusion 20 is disposed between the valve housing 1 and the coupler 14, when the elastic support member S is installed on the fuel injection valve I, by installing it from the side opposite to the coupler 14, the elastic support member S can be easily engaged with the anti-rotation protrusion 20 without interfering with the coupler 14, resulting in good assemblability.

[0057] Furthermore, each elastic piece 16 is composed of a first elastic portion 16a and a second elastic portion 16b. The first elastic portion 16a is connected to one end of the base plate 15 and has a small radius of curvature R1. The second elastic portion 16b extends from the first elastic portion 16a and its end portion 16ba slidably abuts against the upper surface of the other end of the base plate 15 and has a large radius of curvature R2. Therefore, the second elastic portion 16b is supported on the base plate 15 at both ends via the end portion 16ba and the first elastic portion 16a. Thus, even if the first elastic portion 16a undergoes plastic deformation (generally, the part that is bent by reducing the radius of curvature is prone to plastic deformation), the elastic force of the second elastic portion 16b can maintain the force application function of each elastic piece 16 on the fuel supply cover Da. Furthermore, by making the radius of curvature R2 of the second elastic part 16b larger than the radius of curvature R1 of the first elastic part 16a, the height of each elastic piece 16 can be suppressed to a very low level, making it easy to install the elastic support member S into the narrow space between the base surface 5 and the fuel supply cover Da.

[0058] The embodiments of the present invention have been described above, but the present invention is not limited thereto, and various modifications can be made without departing from its spirit. For example, the present invention can also be applied to a structure in which a fuel injection valve I is installed in the intake system of an engine.

[0059] Symbol Explanation

[0060] A: The axis of the valve body;

[0061] D: Fuel distribution pipe;

[0062] Da: Fuel supply cover;

[0063] E: Engine;

[0064] I: Electromagnetic fuel injection valve;

[0065] S: Elastic support component;

[0066] 2: Fuel nozzle cylinder section;

[0067] 3: Electromagnetic coil section;

[0068] 4: Fuel inlet cylinder;

[0069] 5: Base surface;

[0070] 6: Synthetic resin molding section;

[0071] 10: Injection valve mounting hole;

[0072] 14: Coupler;

[0073] 15: Base plate;

[0074] 16: Elastic sheet;

[0075] 16ba: The end portion of the elastic sheet;

[0076] 21: Buckle protrusion;

[0077] 23: First incision;

[0078] 24: Second incision.

Claims

1. A support structure of a fuel injection valve, which has a cylindrical valve housing (1) in a center portion of a fuel injection valve (I), an electromagnetic coil portion (3) being provided in an intermediate portion of the valve housing (1), the electromagnetic coil portion (3) being covered by a synthetic resin molding portion (6), a coupler (14) for supplying power to the electromagnetic coil portion (3) being integrally provided on one side of the synthetic resin molding portion (6), a fuel nozzle cylinder portion (2) of the valve housing (1) being 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 the engine (E) being fitted onto a fuel introduction cylinder portion (4) of the valve housing (1), an elastic support member (S) for applying a force to the valve housing (1) toward the injection valve mounting hole (10) being sandwiched between the valve housing (1) and the fuel supply cap (Da), the elastic support member (S) being composed of: a base plate (15) having a U-shaped notch (19) that receives an outer periphery of the fuel introduction cylinder portion (4), opposing the fuel supply cap (Da), and overlapping a flat base surface (5) provided on a rear end surface of the synthetic resin molding portion (6) toward the fuel introduction cylinder portion (4); and elastic pieces (16) extending from one end of the base plate (15) on a side opposite the notch (19) and elastically contacting an intermediate portion with the fuel supply cap and a terminal end portion with the base plate (15), the synthetic resin molding portion (6) having a rotation stopping protrusion (20) protruding from a transition portion that serves as an extended flat surface extending from the base surface (5) across between the coupler (14) and the fuel introduction cylinder portion (4), the elastic support member (S) having a structure in which a pair of buckle protrusions (21) that buckle engage with an outer peripheral surface of the fuel introduction cylinder portion (4) received in the notch (19) are formed on both inner sides of the notch (19) of the base plate (15), the rotation stopping protrusion (20) being engaged between the notch (19) and the terminal end portions (16ba) of the pair of elastic pieces (16) at the same time as the buckle engagement, in a state in which the fuel injection valve (I) is mounted to the engine (E), as a flexing rebound force of the elastic pieces (16) increases, a contact friction force of the elastic pieces (16) with respect to the base plate (15) increases, so that a buckle engaging force of the buckle protrusions (21) with respect to the fuel introduction cylinder portion (4) increases.

2. The support structure of a fuel injection valve according to claim 1, characterized in that, first cutouts (23) are provided in intermediate portions of both outer sides of the base plate (15).

3. The support structure of a fuel injection valve according to claim 1 or 2, characterized in that, second cutouts (24) are provided on the base plate (15) adjacent to roots of the elastic pieces (16).

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