JPH09242647A - Installation structure of fuel injection nozzle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To position a fuel injection nozzle in a desired rotational position, and besides, fix by pushing/pressing force whose magnitude is in a predetermined range when the fuel injection nozzle is screwed in and fixed to an engine. SOLUTION: A projection 2e collided with to the butt surface of a cylinder head 1 through a gasket 3, is formed in the lower end of a fuel injection nozzle 2. The projection 2e is elastically deformed by pushing/ pressing force which is applied between the butt surfaces 1c, 2c when the fuel injection nozzle 2 is screwed in. Besides, the projection 2e is so formed that it is elastically deformed in a screwing direction of more than one pitch of the screw of a screwing part between the fuel injection nozzle 2 and the cylinder head 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection nozzle mounting structure in which a fuel injection nozzle is directly screwed into and fixed to an engine. In the present invention, the engine means not only a cylinder block and a cylinder head as a main body of the engine but also an intake manifold and the like.

[0002]

2. Description of the Related Art Conventionally, as a mounting structure for mounting a fuel injection nozzle to a cylinder head, a hollow screw, which is separate from the fuel injection nozzle, is provided rotatably and immovably in the axial direction. To be fixed by screwing the female thread formed on the cylinder head (Japanese Utility Model Publication No. 61-29971 and Japanese Utility Model Publication No. 63-428).
No. 66), a flange portion is formed on the fuel injection nozzle, and the flange portion is fixed to the cylinder head with a bolt (see Japanese Utility Model Laid-Open No. 4-79966). A male screw portion is formed on the fuel injection nozzle. However, there is one in which this male screw portion is screwed and fixed to the female screw portion of the cylinder head (see JP-A-57-191451).

In the former two mounting structures, the fuel injection nozzle is provided with a separate hollow screw or a flange portion, so that the space occupied by the fuel injection nozzle is increased accordingly. I will end up. As a result, in the case of a multi-cylinder engine using a large number of fuel injection nozzles, there is a problem in that the layout of the fuel injection nozzles is greatly restricted. In the mounting structure of this point, since the male screw portion is integrally formed with the fuel injection nozzle, the hollow screw and the flange portion are unnecessary, and therefore the occupied space can be reduced. The present invention relates to a mounting structure of.

[0004]

However, the mounting structure of (1) has a problem that it is difficult to mount the fuel injection nozzle at a desired rotational position. That is, in the mounting structure of (1), when the fuel injection nozzle is attached to the cylinder head, the fuel injection nozzle is prevented from loosening due to engine vibration or the like, and the fuel injection nozzle is prevented from being excessively tightened. It is necessary to tighten the nozzle with a pressing force within a predetermined range. However, in the mounting structure, since the male screw portion is directly formed on the fuel injection nozzle, the rotational position of the fuel injection nozzle when a pressing force of a predetermined magnitude is obtained cannot be made constant. For this reason, when attaching a fuel injection nozzle in which a connecting portion for connecting the wire harness is formed on one side, the connecting portion cannot be oriented in a desired direction, and the wire harness is There is a problem that it becomes impossible to connect. Incidentally, in order to deal with such a problem, conventionally, a shim is interposed between the fuel injection nozzle and the cylinder head, and the thickness of the shim is appropriately adjusted,
The fuel injection nozzle is directed in a fixed direction.
However, in such a case, shims having various thicknesses must be prepared in advance, and another problem arises in that it takes a lot of time and effort to select and replace the shims.

[0005]

In order to solve the above problems, the invention according to claim 1 is such that the fuel injection nozzle is screwed into the engine and tightened, and the abutting surface of the fuel injection nozzle is attached to the engine. In a fuel injection nozzle mounting structure in which a fuel injection nozzle is mounted on an engine by abutting against an abutting surface with a pressing force within a predetermined range, the fuel injection nozzle and the engine are butted against each other. A rotation permitting means is provided between the surfaces for permitting the nozzle body screwed to the engine to rotate more than a predetermined angular range while maintaining the pressing force acting on them in the predetermined range. It is characterized by that. In this case, as the rotation permitting means, an elastically deformable portion that is elastically deformable in the abutting direction on the abutting surface of the fuel injection nozzle may be used, or the abutment between the fuel injection nozzle and the engine may be used. Consists of a projecting portion provided on one of the contact surfaces and tapered toward the other side, and a receiving portion provided on the other contact surface and in which the projecting portion bites as the fuel injection nozzle is tightened. Alternatively, a gasket provided between the abutting surfaces of the fuel injection nozzle and the engine and elastically deformable in the abutting direction may be used, and the abutment of the fuel injection nozzle and the engine may be further used. It is also possible to use an annular washer provided between the surfaces and having a corrugated cross section that is elastically deformable in the abutting direction. When a washer is used as the rotation permitting means, both ends of the washer are brought into pressure contact with the abutting surfaces of the fuel injection nozzle and the engine, respectively, to provide a seal material for sealing the abutting surfaces. You may make it shared.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS. FIG. 2 shows an embodiment of the present invention. In this embodiment, a fuel injection nozzle 2 is attached to a cylinder head (engine) 1. The fuel injection nozzle 2 has a connection portion 2a formed on one side thereof to which a wire harness (not shown) is connected, and a male screw portion 2b formed on an outer peripheral surface of an intermediate portion thereof.
Are formed. Then, in the fuel injection nozzle 2, the male screw portion 2b is screwed into the female screw portion 1b of the mounting hole 1a of the cylinder head 1 and tightened, and the abutting surface 2c is attached to the abutting surface 1c of the cylinder head 1 with the annular gasket 3. It is fixed to the cylinder head 1 by abutting against it.

Inside the fuel injection nozzle 2, there are provided a valve body for opening and closing the injection hole, a valve spring and a solenoid for opening and closing the valve body (all not shown), and the injection hole is opened when the valve is opened. The fuel is injected into the combustion chamber A from the above, but since they are similar to the conventional fuel injection nozzle, the description thereof is omitted here. The gasket 3 is made of a metal softer than the material forming the cylinder head 1 and the fuel injection nozzle 2, such as aluminum or copper.

As shown in FIGS. 1A and 1B, an annular groove 2d extending in the circumferential direction is formed on the outer peripheral surface of the lower end portion of the fuel injection nozzle 2. The diameter of the bottom surface of the annular groove 2d is smaller than the inner diameter of the gasket 3. Also,
By forming the annular groove 2d, the fuel injection nozzle 2
An annular projecting portion (elastically deforming portion) 2e is formed at the lower end portion of the. The protruding portion 2e is slightly inclined downward so as to approach the abutting surface 1c toward the tip side (outer peripheral side), and the tip portion of the lower surface (outer peripheral portion of the abutting surface 2c). Abuts on the abutting surface 1c via the gasket 3.

The projecting portion 2e is elastically deformable so that the tip end portion is displaced upward, and when the fuel injection nozzle 2 is screwed in while abutting against the gasket 3, it elastically deforms in accordance with the screwing distance, and Abutting surface 1
A pressing force is applied between c and 2c. In this case, when the entire protruding portion 2e is substantially horizontal, the pressing force acting between the abutting surfaces 1c, 2c is set to be within a predetermined range.

FIG. 3 shows the screwing distance of the fuel injection nozzle 2 and the abutting surfaces 1c, 2 due to the elastic deformation of the protruding portion 2e.
It is a figure which shows the relationship with the pressing force which acts between c, Comprising: When the fuel injection nozzle 2 is screwed in from the state where the protrusion 2e was simply contacting the gasket 3, the pressing force increases according to the screwing distance. Then, when the fuel injection nozzle 2 is screwed in by the distance A, the pressing force reaches the lower limit value of the pressing force required to fix the fuel injection nozzle 2, and when it is screwed in the distance B, it reaches the upper limit value. Here, the distance (B) at which the fuel injection nozzle 2 is screwed in from the time when the lower limit is reached to the time when the upper limit is reached (B
-A) is larger than the screwing distance per one rotation of the fuel injection nozzle 2, that is, one pitch of the male screw portion 2b (female screw portion 1b). Therefore, the fuel injection nozzle 2
Can rotate one or more times in a state where the pressing force acting between the abutting surfaces 1c and 2c is maintained within a predetermined range between the lower limit value and the upper limit value.

When the fuel injection nozzle 2 is attached to the cylinder head 1 in the attachment structure constructed as described above, the fuel is first applied until the pressing force acting between the abutting surfaces 1c, 2c reaches a predetermined lower limit value. The injection nozzle 2 is screwed into the cylinder head 1. After that, the fuel injection nozzle 2 is further screwed in until the connecting portion 2a first faces the predetermined direction. This completes the mounting of the fuel injection nozzle 2.

Here, the connecting portion 2a is the fuel injection nozzle 2
Make sure to turn to the specified direction during one revolution of. Moreover, the fuel injection nozzle 2 can rotate more than one revolution before the pressing force acting between the abutting surfaces 1c and 2c reaches the upper limit value from the lower limit value. Therefore, the fuel injection nozzle 2
Can be fixed to the cylinder head 1 with a pressing force within a predetermined range, and the connecting portion 2a can be oriented in a predetermined direction.

Further, in this embodiment, the protrusion 2e is initially inclined obliquely downward and becomes substantially horizontal when the pressing force reaches the range of a predetermined magnitude.
As is clear from the above, the increasing rate of the pressing force is large at the beginning and becomes smaller as the protrusion 2e becomes substantially horizontal. Therefore, it is possible to increase the screwing distance (BA) at which the fuel injection nozzle 2 can be screwed in while the pressing force reaches the upper limit value from the lower limit value. Therefore, even if the relationship between the screwing distance and the pressing force becomes different from the set value due to a manufacturing error such as a thickness error of the protruding portion 2e, such an error can be sufficiently absorbed, and it is possible to reliably perform the operation. The connecting portion 2a can be directed in a desired direction.

In this embodiment, the pressing force acting on the abutting surfaces 1c, 2c is maintained within a predetermined range while the fuel injection nozzle 2 rotates one rotation or more. When there is a permissible value for the direction of the connecting portion 2a, it is necessary to maintain the pressing force within a predetermined range.
It may be rotated or less. For example, if the direction of the connecting portion 2a is
There is a certain allowable value (allowable angle) in the forward / reverse rotation direction with respect to the reference value, and the allowable value in the forward / reverse direction is α ° and β respectively.
.Degree., The minimum rotation angle .theta. Required to maintain the pressing force acting on the abutting surfaces 1c, 2c within a predetermined range is .theta. = 360.degree .- (. Alpha. +. Beta.).

Further, in the above embodiment, the fuel injection nozzle 2 is further screwed in until the connecting portion 2a faces a predetermined direction after the pressing force acting on the abutting surfaces 1c, 2c reaches the lower limit value. However, after screwing until the pressing force acting on the abutting surfaces 1c, 2c reaches the upper limit,
The fuel injection nozzle 2 may be unscrewed until the connecting portion 2a faces the predetermined direction.

Further, in the above-described embodiment, the rotational speed of the fuel injection nozzle 2 which is rotated after the pressing force acting on the abutting surfaces 1c, 2c reaches the lower limit value and before the connecting portion 2a faces a predetermined direction. Is less than one revolution, but the distance (B-
When A) is 2 pitches or more, it is possible to rotate more than one rotation, whereby the abutting surface 1
The pressing force acting on c and 2c can be appropriately adjusted within a predetermined range.

Next, another embodiment of the present invention will be described. FIG. 4 shows a second embodiment of the present invention. In this embodiment, the abutting surface 2c is
A projecting portion (elastically deformable portion) 2f having a substantially L-shaped cross section and projecting downward is formed at. The lower end surface 2g of the protruding portion 2f is formed into a curved surface having a substantially arcuate cross section that bulges downward, and the lowest position P of the protruding portion 2f abuts the gasket 3. Since the abutting point P is located on the outer peripheral side of the central portion in the thickness direction (radial direction) of the protruding portion 2f, when the fuel injection nozzle 2 is screwed in, the protruding portion 2f is, as shown by an imaginary line, The lower end is elastically deformed so as to be displaced to the outer peripheral side and to be displaced upward. Then, by utilizing this elastic deformation, the abutting surfaces 1c and 2c are the same as in the above embodiment.
While maintaining the pressing force that acts on the size of the specified range,
The fuel injection nozzle 2 is allowed to rotate once or more.

FIG. 5 shows a third embodiment of the present invention. In this embodiment, the abutting surface 2 is shown.
Two annular protrusions 2h having a wedge shape with a substantially triangular cross section are concentrically formed on c. Then, the protruding portion 2h is made to bite into the gasket (receiving portion) 3A made of a relatively soft metal such as copper or aluminum so that the pressing force acting between the abutting surfaces 1c and 2c can be increased within a predetermined range. While maintaining the above, the fuel injection nozzle 2 is allowed to rotate one rotation or more.

6 and 7 show a fourth embodiment of the present invention. In this embodiment,
Although the same fuel injection nozzle 2 as the conventional one is used as the fuel injection nozzle 2, a gasket 3B is used instead of the gasket 3 of the above-described embodiment. The gasket 3B has a substantially U-shaped cross section with an open outer peripheral side, and is elastically deformable in its axial direction (pressing direction). This allows the fuel injection nozzle 2 to rotate by a predetermined angle (predetermined rotation speed) while maintaining the pressing force acting between the abutting surfaces 1c and 2c within a predetermined range. Has become.

8 to 11 show gaskets 3B, respectively.
In each drawing, the shape before elastic deformation is shown by a solid line, and the shape after elastic deformation is shown by an imaginary line. The gasket 3C shown in FIG. 8 has an H-shaped cross section. The gasket 3D shown in FIG. 9 has a concave cross section. Gasket 3 shown in FIG.
E has a K-shaped cross section. The gasket 3F shown in FIG. 11 is formed in an N-shaped cross section.

FIG. 12 shows still another embodiment of the present invention. In this embodiment, a wavy annular washer 4 is arranged between the abutting surface 2c and the gasket 3. ing. The washer 4 is elastically deformable in the axial direction (abutting direction), and by utilizing the elastic deformation, the pressing force acting between the abutting surfaces 1c and 2c is maintained within a predetermined range. While
The fuel injection nozzle 2 is allowed to rotate by a predetermined angle (a predetermined number of rotations). Further, the upper surface of the washer 4 is abutted against the abutting surface 2c and the lower surface thereof is abutted against the gasket 3, so that airtightness between them is secured, and thus airtightness between the abutting surfaces 1c, 2c is secured. Has become.

[0022]

As described above, according to the first to sixth aspects of the present invention.
According to the invention, the fuel injection nozzle can be tightened with a predetermined pressing force and can be positioned at a desired rotational position (direction). Moreover, since it is not necessary to prepare or replace shims having various thicknesses, the manufacturing cost can be reduced accordingly.

[Brief description of drawings]

1A and 1B are views showing an embodiment of the present invention, in which FIG. 1A is a sectional view showing a main part thereof, and FIG.
It is an enlarged view of the B circle part of (A).

FIG. 2 is a sectional view showing an embodiment of the present invention.

FIG. 3 is a diagram showing a relationship between a screwing distance and a pressing force of the fuel injection nozzle in the embodiment shown in FIGS. 1 and 2.

FIG. 4 is a view showing a second embodiment of the present invention, FIG.
It is a sectional view similar to FIG.

FIG. 5 (B) showing a third embodiment of the present invention.
It is a sectional view similar to FIG.

FIG. 6 is a sectional view similar to FIG. 1A showing a fourth embodiment of the present invention.

7 is a partially omitted enlarged cross-sectional view showing a gasket used in the embodiment shown in FIG.

FIG. 8 is a view showing a modified example of the gasket according to the present invention.
It is a sectional view similar to FIG.

FIG. 9 is a view showing a modified example of the gasket according to the present invention.
It is a sectional view similar to FIG.

FIG. 10 is a sectional view similar to FIG. 7, showing a modified example of the gasket according to the present invention.

FIG. 11 is a sectional view similar to FIG. 7, showing a modified example of the gasket according to the present invention.

FIG. 12 is a view showing still another embodiment of the present invention.
It is a sectional view similar to FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder head (engine) 1a Mounting hole 1b Female screw part 1c Abutting surface 2 Fuel injection nozzle 2a Connecting part 2b Male screw part 2c Abutting surface 2e Projecting part (elastically deforming part) 2f Projecting part (elastically deforming part) 2h Projecting part 3 Gasket 3A Gasket (receiving part) 3B Gasket 3C Gasket 3D Gasket 3E Gasket 3F Gasket 4 Washer

Claims (6)

[Claims] 1. Fuel injection by screwing a fuel injection nozzle to an engine and tightening it, and abutting the abutting surface of the fuel injection nozzle against the abutting surface of the engine with a pressing force within a predetermined range. In a fuel injection nozzle mounting structure in which a nozzle is mounted on an engine, a pressing force acting on the fuel injection nozzle and the engine is kept within a predetermined range between abutting surfaces of the fuel injection nozzle and the engine. At the same time, a mounting structure for a fuel injection nozzle is provided, which is provided with rotation permitting means for permitting the nozzle body screwed into the engine to rotate more than a predetermined angle range. 2. The fuel injection nozzle mounting structure according to claim 1, wherein, as the rotation permitting means, an elastically deformable portion that is elastically deformable in an abutting direction is formed on an abutting surface of the fuel injection nozzle. Characteristic fuel injection nozzle mounting structure. 3. The fuel injection nozzle mounting structure according to claim 1, wherein the rotation permitting means is provided on one of the abutting surfaces of the fuel injection nozzle and the engine, and tapers toward the other side. A structure for mounting a fuel injection nozzle, comprising: a protruding portion formed; and a receiving portion that is provided on the other butting surface and that the protruding portion bites when the fuel injection nozzle is tightened. 4. The fuel injection nozzle mounting structure according to claim 1, wherein the rotation permitting means is provided between abutment surfaces of the fuel injection nozzle and the engine, and is elastically deformable in an abutment direction. A structure for mounting a fuel injection nozzle characterized by using a certain gasket. 5. The fuel injection nozzle mounting structure according to claim 1, wherein the rotation permitting means is provided between abutment surfaces of the fuel injection nozzle and the engine, and is elastically deformable in an abutment direction. A structure for mounting a fuel injection nozzle, wherein an annular washer having a wavy cross section is used. 6. The fuel injection nozzle mounting structure according to claim 5, wherein both ends of the washer are pressed into contact with the abutting surfaces of the fuel injection nozzle and the engine, respectively, so that the washer is ejected. A structure for mounting a fuel injection nozzle, which is also used as a sealing material for sealing between contact surfaces.