JPH11257193A - Nozzle holder clamping structure of direct injection-type diesel engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve mounting accuracy of a fuel injection nozzle of a direct injection-type diesel engine to a cylinder head. SOLUTION: A spherical projecting supporting surface 11b is formed on the lower part of a fulcrum part 11B of a bridge-shaped nozzle clamp 11 in relation to a cylinder head E, an circular projecting pressing surface 11a is formed on the lower part of a pressing part 11A for pressing a holder pressure receiving surface 4b of a shoulder part of a nozzle holder 4B, and the central part is clamped to the cylinder head E by a clamp bolt 2 in which a spherical washer 3 is interposed. Eccentric pressing of the nozzle holder 4B is avoided by restraining tilting of the nozzle clamp 11 by the spherical projecting fulcrum surface 11b even if the horizontal degree error in the width direction exists as well as by adsorbing the error in the height direction of the fulcrum surface Ba of the cylinder head E and the nozzle holder pressure receiving surface 4b, and therefore, irregular injection of a fuel injection nozzle is prevented, and assembling productivity is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for fixing an injection nozzle holder of a direct injection diesel engine, and more particularly to a method for fixing a nozzle holder by a bridge type nozzle holder clamp.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional nozzle holder clamp (hereinafter abbreviated as "clamp") 1 and a peripheral portion thereof. The clamp 1 includes the nozzle 4A and the nozzle holder 4
B and the like, the fuel injection nozzle 4
And plays an auxiliary role of supplying high-pressure fuel from the fuel injection pump (not shown) via the injection pipe P to the engine EC.

Such a clamp 1 is generally formed in a bridge shape, and one end is provided at a head fulcrum surface Ba of a cylinder head E.
In this figure, the upper end of the head bolt B is brought into contact with the upper surface of the head to serve as a fulcrum, and the other end presses the holder pressure receiving surface 4b of the holder shoulder formed on the upper part of the nozzle holder 4B, thereby clamping the clamp bolt 2 at the center. To the cylinder head E.

[0004] In order to fix the fuel injection nozzle 4 accurately without distortion, the holder pressing surface 1a is set as shown in FIG.
The downwardly convex arcuate curved surface shown in (b) prevents the pressing from being eccentric due to an error in the height direction of the holder pressure receiving surface 4b. Further, a fulcrum surface 1b that abuts on the head fulcrum surface Ba at the other end is also a downwardly convex arcuate curved surface (FIG.
(See (c)), an error in the vertical dimension between the holder pressure receiving surface 4b and the head fulcrum surface 1b and a parallelism error between the two surfaces prevent the fuel injection nozzle 4 from being biased. Also, a spherical washer 3 is attached to the lower side of the bolt head of the clamp bolt 2 for fixing the clamp 1, and the clamp 1 in FIG. 5A is attached to a spherical seat formed above the bolt hole 1 </ b> D of the clamp 1. The rotation at the time is allowed to facilitate installation.

In such a fuel injection nozzle mounting structure, the clamp may be rotated by a tightening force when the clamp bolt is tightened to the cylinder head, and may interfere with a nearby component. A technique in which a bolt is provided has been disclosed (see Japanese Patent Application Laid-Open No. 5-89870). Further, there is disclosed a technique in which a mounting hole for a nozzle holder is provided in a rocker cover, and a sealing member is interposed between the mounting hole and the nozzle holder to improve the sealing property (Japanese Utility Model Application Laid-Open No. 58-30763). Gazette).

Further, a technique has been disclosed in which a clamp is extruded from an aluminum alloy to reduce its weight and cost (see JP-A-8-303326).

[0007]

In a conventional bridge-like clamp as described above, the head support surface Ba is formed as shown in FIG.
In the case where the head is inclined in the width direction perpendicular to the paper surface in FIG. 6A, that is, as shown in FIG.
The fulcrum portion 1B is tilted like CB, so the holder pressing portion 1A
Tilt and hit the holder pressure receiving surface 4b. This uneven contact causes poor assembly of the fuel injection nozzle assembly 4 and irregular injection.

The present invention has been made in view of the above-described conventional circumstances, and has as its object to prevent a fuel injection nozzle from being improperly assembled due to a flatness error in a width direction of a head support surface.

[0009]

According to a first aspect of the present invention, there is provided a cylinder head which accommodates a fuel injection nozzle and is mounted on a cylinder head and which is fastened to the cylinder head via a bolt. And a bridge-type nozzle holder clamp for pressing and holding the nozzle holder at the other end with the one end in contact with the nozzle holder clamp structure of the direct injection diesel engine. A spherical projection is formed on an end face of the nozzle holder, and an arc-shaped projection is formed on an end face of the nozzle holder that presses and holds the nozzle holder.

Accordingly, even if the head fulcrum surface at the top of the cylinder head is inclined in the horizontal plane in the width direction, the nozzle holder clamp has almost no inclination due to the spherical clamp fulcrum surface, so that it is possible to prevent the fuel injection nozzle from being improperly assembled.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. The same components as those described in the related art are denoted by the same reference numerals. 1 to 3, a clamp 11 is integrally formed in a bridge shape, and a fulcrum portion 11B that comes into contact with the cylinder head E as a fulcrum, a holder pressing portion 11A that presses a shoulder of the nozzle holder 4B, and a fulcrum portion 1.
A main part is formed by a bolt hole 11C, which is located between the holder pressing part 11A and the holder pressing part 11A and through which the clamp bolt 2 penetrates.

The fulcrum portion 11B has a fulcrum surface 11b of a spherical projection projecting downward at a lower end portion. The front end of the holder pressing portion 11A branches in a U-shape, and the nozzle holder 4B
Is pressed so as to sandwich the shoulder from both sides in the vertical direction. A pressing surface 11a of a downwardly convex arc-shaped projection is formed at a lower end of the U-shaped branched holder pressing portion 11A.

The bolt hole 11C is vertically penetrated, and a spherical seat 11D is formed at the upper end so that the inclination of the clamp 11 is supported by the seat surface together with the spherical washer 3. Next, the operation will be described. 1 to 3, the pressing surface 11a of the holder pressing portion 11A is placed on the holder pressure receiving surface 4b of the nozzle holder 4B attached to the cylinder head E, and the holder fulcrum 1 is mounted on the fulcrum surface Ba of the cylinder head E.
1B, the fulcrum surface 11b is placed correctly, the bolt 11C penetrates the bolt hole 11C, the clamp bolt 2 with the spherical washer 3 interposed therebetween presses the spherical seat 11D, and the clamp 11
Is concluded.

The clamp bolt 2 is connected to the cylinder head E
When the head fulcrum surface Ba is a CBa inclined in the width direction shown in FIG. 4, the fulcrum S moves to S1, but is very small. Due to the deformation between the CBas, the movement of the fulcrum is further reduced. Therefore, the inclination of CBa is maintained as it is in the nozzle holder 4B.
In the nozzle clamp 11, eccentric pressing can be almost avoided as compared with the conventional structure in which eccentric pressing is performed.

The error and the parallelism error with respect to a predetermined difference in the vertical direction between the holder pressure receiving surface 4b and the fulcrum surface Ba are as follows.
There is no problem that can be avoided as in the past.

[0016]

As described above, according to the present invention,
The fulcrum of the nozzle clamp is formed by a spherical projection, and the pressing part that presses the nozzle holder is an arc-shaped projection, so that the pressing of the nozzle holder due to the height error between the fulcrum surface of the cylinder head and the pressing surface of the nozzle holder is performed. Even if there is no eccentricity, and even if there is an error in the parallelism in the width direction between the pressing surface of the nozzle holder and the fulcrum surface of the head, the inclination of the clamp is very small, preventing the nozzle holder from being biased and lowering the function of the fuel injection nozzle. Without this, the assembly workability is also improved.

[Brief description of the drawings]

1A is a side view showing a state where a clamp of the present invention is mounted, FIG. 1B is a front view of a fulcrum, and FIG. 1C is a front view of a holder pressing portion.

FIG. 2 is a top view of the same clamp.

FIG. 3 is a side view of the above.

FIG. 4 is a view showing the operation of the fulcrum surface of the above.

5A is a side view showing a state in which a conventional clamp is attached, FIG. 5B is a view of a fulcrum portion and a head fulcrum surface as viewed from an arrow X, FIG. 5C is a perspective view of the fulcrum portion, and FIG. Y arrow view of the holder pressing portion and the holder

FIG. 6 is a view showing the operation of the fulcrum surface of the above.

[Explanation of symbols]

 Ba head fulcrum surface E cylinder head 2 clamp bolt 3 spherical washer 4 fuel injection nozzle 4B nozzle holder 4b holder pressure receiving surface 11 nozzle clamp 11A pressing portion 11a pressing surface 11B fulcrum portion 11b fulcrum surface 11C bolt hole 11D spherical seat

Claims (1)

[Claims] 1. A nozzle holder which accommodates a fuel injection nozzle and is attached to a cylinder head. The nozzle holder is fastened to the cylinder head via bolts, and the nozzle holder is pressed and held at the other end with one end being in contact with the cylinder head as a fulcrum. A bridge-shaped nozzle holder clamp, comprising: a nozzle holder clamp structure for a direct injection diesel engine, the spherical holder having a downwardly projecting spherical projection formed on an end surface of the nozzle holder clamp on a side in contact with a cylinder head. A nozzle holder clamp structure for a direct-injection diesel engine, wherein an arc-shaped projection protruding downward is formed on an end surface on a side for pressing and holding the nozzle.