JP7697991B2 - Fuel-injected engine - Google Patents

Description

The present invention relates to a fuel-injected engine, and more specifically, to a fuel-injected engine that allows a high degree of freedom in component placement within a narrow cylinder head cover and maintains high fuel injection accuracy of the fuel injector.

Prior to the present invention, the inventor of the present invention proposed the fuel injection engine shown in FIGS.
As shown in Figures 1 and 2, the fuel injection engines of Proposed Examples 1 and 2 include a fuel injector (2) inserted into an injector insertion hole (1a) in a cylinder head (1), a rocker arm bracket (3) arranged inside a cylinder head cover (not shown), stud bolts (4) for fixing the rocker arm bracket (3) to the cylinder head (1), and a clamp (5) arranged on the upper side of the rocker arm bracket (3), and are configured so that the fuel injector (2) is pressed and fixed inside the injector insertion hole (1a) by the pressing force of the clamp (5).
A conventional technique for this type of engine is disclosed in Japanese Patent Application Laid-Open No. 2003-233666.

JP 2021-110231 A (see FIG. 1)

Problem 1: The freedom of component placement within the narrow cylinder head cover is reduced.
In the prior proposed example 1 shown in FIG. 1 , a fuel injector 2 is inserted into an injector insertion hole 1 a, and a bifurcated clamp 5 is fitted to a small-diameter intermediate body portion 2 a below a large-diameter portion 2 b at the top of the fuel injector 2 by a lateral slide S along the diameter of the small-diameter intermediate body portion 2 a. The clamp 5 is then pressed by the tightening force of a headed bolt 20 to press against a pressure-receiving portion 2 aa of the intermediate body portion 2 a.
As a result, the bolt mounting portion (20a) of the headed bolt (20) bulges out from the rocker arm bracket (3) towards the fuel injector (2), and this bolt mounting portion (20a) gets in the way, reducing the freedom of arrangement of the fuel injector (2) and its surrounding parts such as the intake and exhaust valves, valve springs, valve retainers, etc., not shown, within the narrow cylinder head cover (not shown).
The invention of Patent Document 1 has the same problem.

Problem 2: The fuel injection accuracy of the fuel injector (2) may decrease.
In the previous proposed example 2 shown in FIG. 2 , the fuel injector (2) is inserted into the injector insertion hole (1a), and the clamp (5) fitted around the stud bolt (4) is lowered (D) along the stud bolt (4), and a pressing force is applied to the clamp (5) by the tightening force of the nut (4a) screwed onto the stud bolt (4). However, when the bifurcated clamp (5) is lowered (D), the clamp (5) comes into contact with the large diameter portion (2b) of the fuel injector (2) located above the intermediate body portion (2a), and the lowering (D) is restricted. Therefore, a pressure-receiving portion (2aa) is formed in the large diameter portion (2b), and this is pressed by the clamp (5).
As a result, the fuel injector 2 is pressed at a high position, which can cause precision parts inside the fuel injector 2 to deform due to buckling, resulting in a decrease in the fuel injection accuracy of the fuel injector 2.

The objective of the present invention is to provide a fuel-injected engine that allows a high degree of freedom in component placement within the narrow cylinder head cover and maintains high fuel injection accuracy of the fuel injector.

The main configuration of the present invention is as follows.
A fuel injection engine comprising a fuel injector (2) inserted into an injector insertion hole (1a) of a cylinder head (1) as shown in FIG. 3, a rocker arm bracket (3) arranged within a cylinder head cover (1b) as shown in FIG. 4(B), a stud bolt (4) for fixing the rocker arm bracket (3) to the cylinder head (1), and a clamp (5) arranged on the upper side of the rocker arm bracket (3) as shown in FIG. 3, wherein the fuel injector (2) is pressed and fixed within the injector insertion hole (1a) by the pressing force of the clamp (5),
As shown in FIG. 3, the fuel injector 2 includes a pressure receiving portion 2aa in a middle portion 2a located in the middle of the axial length of the fuel injector.
As shown in FIG. 3, the clamp (5) includes a main clamp (6) and a sub clamp (7), the sub clamp (7) is fitted onto the intermediate body portion (2a) of the fuel injector (2), and the main clamp (6) is disposed on the upper portion of the rocker arm bracket (3) and fitted onto the stud bolt (4).
As shown in FIG. 3 , a fuel injection engine is configured such that a main clamp (6) presses a pressure-receiving portion (2aa) of a middle portion (2a) of a fuel injector (2) via a sub-clamp (7) below it by the fastening force of a nut (4a) screwed onto a stud bolt (4).

The present invention has the following advantages.
<Effect 1> The degree of freedom in component placement within the narrow cylinder head cover (1b) is increased.
As shown in FIG. 3, in this invention, the stud bolts 4 that secure the rocker arm bracket 3 are also used as mounting bolts for the main clamp 6. This means that, unlike the inventions of the previous proposed example 1 and Patent Document 1, it is no longer necessary to have the bolt mounting portion 20a of the headed bolt 20 shown in FIG. 1 bulge out from the rocker arm bracket 3 toward the fuel injector 2. This increases the freedom of arrangement of the fuel injector 2 and its surrounding parts such as the intake and exhaust valves, valve springs, valve retainers, etc. within the narrow cylinder head cover 1b shown in FIG. 4(B).

<Effect 2> The fuel injection accuracy of the fuel injector (2) can be maintained at a high level.
As shown in FIG. 3 , in this invention, sub-clamp 7 is fitted onto the outer periphery of mid-body portion 2a of fuel injector 2, and the fastening force of nut 4a screwed onto stud bolt 4 causes main clamp 6 to press pressure-receiving portion 2aa of mid-body portion 2a of fuel injector 2 via sub-clamp 7 located below it. Therefore, unlike previous proposed example 2 shown in FIG. 2 , fuel injector 2 is pressed at a low position, making deformation of precision parts inside fuel injector 2 due to buckling less likely to occur, and the fuel injection accuracy of fuel injector 2 can be maintained at a high level.

Effect 3: The clamp (5) can be repaired inexpensively.
As shown in FIG. 3, in this invention, the clamp (5) is composed of a main clamp (6) and a sub clamp (7), so that if the sub clamp (7) wears out early, it is possible to repair the clamp (5) at low cost by replacing only the sub clamp (7).

FIG. 2 is a perspective view of a main part of the first proposed example. FIG. 11 is a perspective view of a main part of the previous proposed example 2. FIG. 2 is a perspective view of a main portion of an embodiment of the present invention. 4A and 4B are diagrams for explaining the main part of an embodiment of the present invention, with FIG. 4A being a plan view and FIG. 4B being a front view. 5A is a plan view of a main clamp used in an embodiment of the present invention, FIG. 5B is a front view, and FIG. 5C is a view seen in the direction of an arrow C in FIG. 5A. 6A is a plan view of a sub-clamp used in an embodiment of the present invention, FIG. 6B is a front view, and FIG. 6C is a view seen in the direction of an arrow C in FIG. 6A.

Figures 1 and 2 are previous proposals, and Figures 3 to 5 are diagrams explaining a fuel injection engine according to an embodiment of the present invention. In this embodiment, a common rail type, multi-valve type, in-line multi-cylinder vertical diesel engine is explained.

In this engine, a plurality of cylinders are arranged side by side in the direction in which a crankshaft (not shown) is installed.
In the previously proposed examples and embodiments of this invention, the installation direction of the crankshaft is illustrated and described as the front-to-rear direction, one side of the front-to-rear direction, for example the side where the engine cooling fan or radiator is located, is referred to as the front, the other side, for example the side where the flywheel is located, is referred to as the rear, the width direction of the engine is referred to as the left-to-right direction, the left-hand side of an observer facing forward at the engine position is referred to as the left, the right-hand side is referred to as the right, and the height direction of the engine is referred to as the up-down direction.

The engine includes an intake system, a fuel supply system, and an exhaust system.
Although not shown, the intake and exhaust system includes intake and exhaust ports, intake and exhaust valves, and a valve train.
Intake and exhaust ports (not shown) are formed in the cylinder head (1) shown in FIG. 4(B), and the intake and exhaust valves are of a four-valve type with two intake valves and two exhaust valves for each cylinder, and are arranged around the fuel injector (2).
The valve train (not shown) is of the overhead valve type equipped with a valve camshaft, a push rod, and a rocker arm.
The rocker arm (not shown) is pivotally supported on a rocker arm pivot (3a) supported on a rocker arm bracket (3) shown in FIG. 4(A).

The fuel supply system includes an engine ECU (electronic engine control unit) (not shown), a fuel supply pump, a common rail, and a fuel supply pipe.
The fuel supply system includes a fuel injector (2) shown in FIG. 3 that is provided for each cylinder, and liquid fuel (diesel) stored in a common rail is pressure-fed from a fuel supply pipe to the fuel injector (2). A fuel injection valve of the fuel injector (2) is opened for a predetermined time at a predetermined timing by electronic control, and a predetermined amount of fuel is injected from the fuel injector (2) into each cylinder at a predetermined timing.

As shown in FIG. 4(B), the rocker arm bracket (3) is placed and fixed to the upper surface of the cylinder head (1) and is housed in a cylinder head cover (1b) which is placed and fixed to the upper surface of the cylinder head (1).
As shown in FIG. 4(B), in this engine, stud bolts (4) are screwed into and fixed to the cylinder head (1), the stud bolts (4) stand up from the upper surface of the cylinder head (1), a rocker arm bracket (3) is fitted onto the outside of this stud bolt (4), and the rocker arm bracket (3) is pressed and fixed to the upper surface of the cylinder head (1) by the tightening force of a bracket fixing nut (4c) that is screwed into the middle part of the stud bolt (4).

As shown in FIG. 4(B), the fuel injector 2 is inserted into the injector insertion hole 1a of the cylinder head 1 at a portion thereof near the tip, and an annular copper packing 1c is disposed between a downward injector pressing surface 2e provided on the portion of the fuel injector 2 near the tip and the rear end face 1aa of the injector insertion hole 1a. The pressing force applied to the fuel injector 2 presses and fixes the injector pressing surface 2e against the rear end face 1aa of the injector insertion hole 1a via the annular packing 1c, and the space between the injector pressing surface 2e and the rear end face 1aa of the injector insertion hole 1a is sealed by the annular packing 1c held between them.
As shown in FIG. 4B, the gap between the inner peripheral surface of the injector insertion hole 1a and the outer peripheral surface of the fuel injector 2 is sealed by a pair of upper and lower O-rings 1d, 1d.

As shown in FIG. 3, this engine includes a fuel injector (2) inserted into the injector insertion hole (1a) of the cylinder head (1), a rocker arm bracket (3) arranged inside the cylinder head cover (1b) shown in FIG. 4(B), and, as shown in FIG. 3, a stud bolt (4) that fixes the rocker arm bracket (3) to the cylinder head (1), and a clamp (5) arranged on the upper side of the rocker arm bracket (3). The fuel injector (2) is pressed and fixed inside the injector insertion hole (1a) by the pressing force of the clamp (5).

As shown in FIG. 3, the fuel injector 2 is provided with a pressure-receiving portion 2aa in an intermediate body portion 2a located in the middle of its axial length.
As shown in FIG. 3, the clamp (5) includes a main clamp (6) and a sub clamp (7). The sub clamp (7) is fitted onto the intermediate body portion (2a) of the fuel injector (2), and the main clamp (6) is disposed on the upper side of the rocker arm bracket (3) and fitted onto the stud bolt (4).
As shown in FIG. 3, in this engine, a main clamp (6) is configured to press a pressure-receiving portion (2aa) of a middle body portion (2a) of a fuel injector (2) via a sub-clamp (7) below it by the fastening force of a nut (4a) screwed onto a stud bolt (4).

As shown in FIG. 3, in this engine, the stud bolts (4) that secure the rocker arm bracket (3) also serve as mounting bolts for the main clamp (6). This means that, unlike the inventions of Proposal Example 1 and Patent Document 1, it is no longer necessary to have the bolt mounting portion (20a) shown in FIG. 1 bulge out from the rocker arm bracket (3) toward the fuel injector (2). This increases the freedom of arrangement of the fuel injector (2) and its surrounding parts, such as the intake and exhaust valves, valve springs, and valve retainers, within the narrow cylinder head cover (1b) shown in FIG. 4(B).

As shown in FIG. 3, in this engine, the sub-clamp (7) is fitted onto the middle body (2a) of the fuel injector (2), and the tightening force of the nut (4a) screwed onto the stud bolt (4) causes the main clamp (6) to press the pressure-receiving portion (2aa) of the fuel injector (2) through the sub-clamp (7) below. Therefore, unlike the previous proposed example 2, the fuel injector (2) is pressed at a low position, which makes it difficult for the precision parts inside the fuel injector (2) to deform due to buckling, and the fuel injection accuracy of the fuel injector (2) can be maintained at a high level.

As shown in Figure 3, in this engine, the clamp (5) is composed of a primary clamp (6) and a secondary clamp (7). Therefore, if the secondary clamp (7) wears out prematurely, only the secondary clamp (7) can be replaced and the clamp (5) can be repaired inexpensively.

As shown in FIG. 3, in this engine, the fuel injector (2) is provided with a large diameter portion (2b) that protrudes radially outward above the secondary clamp (7).
As shown in FIG. 5(A), the main clamp (6) has a pair of pressing portions (6a) (6a) branched into two branches, and a separation dimension (6aD) between the pair of pressing portions (6a) (6a) is formed to be larger than a diameter dimension (2bD) of the large diameter portion (2b) of the fuel injector (2).
As shown in FIG. 3, in this engine, when the main clamp 6 fitted around the stud bolt 4 is lowered (D) along the stud bolt 4 during clamping of the fuel injector 2, the pair of pressing portions 6a, 6a of the main clamp 6 pass either side of the large diameter portion 2b of the fuel injector 2 and come into contact with the pair of pressure receiving portions 7a, 7a of the sub-clamp 7.

As shown in FIG. 3, in this engine, even if the fuel injector (2) has a large diameter portion (2b), the main clamp (6) fitted onto the stud bolt (4) can be lowered (D) along the stud bolt (4) without being hindered by the large diameter portion (2b). By simply abutting the main clamp (6) against the pressure receiving portion (7a) of the sub-clamp (7) and tightening the nut (4a) screwed onto the stud bolt (4), the main clamp (6) can press the pressure receiving portion (2aa) of the fuel injector (2) via the sub-clamp (7) below, making the clamping operation of the fuel injector (2) easy.

As shown in FIG. 3, in this engine, the pressure-receiving portion (7a) of the secondary clamp (7) protrudes outward from both sides of the U-shaped fitting portion (7b) that is fitted onto the intermediate body portion (2a) of the fuel injector (2), and is positioned radially outward from the large diameter portion (2b) of the fuel injector (2).

In this engine, even if the fuel injector (2) has a large diameter portion (2b), interference between the large diameter portion (2b) and the main clamp (6) during the clamping operation of the fuel injector (2) can be avoided by simply protruding the pressure receiving portion (7a) of the sub-clamp (7) outward from both sides. The pressing portion (6a) of the main clamp (6) can pass through both sides of the large diameter portion (2b) of the fuel injector (2). This means that there is no need to change the structure of the fuel injector (2), such as by reducing the diameter of the large diameter portion (2b) of the fuel injector (2), and the fuel injection accuracy of the fuel injector (2) can be maintained at a high level.

As shown in FIG. 3 or FIG. 4(A), in this engine, the intermediate body portion (2a) of the fuel injector (2) has a pair of flat surfaces (2c)(2c) on both sides that are recessed toward the center, and the sub-clamp (7) fitted onto the intermediate body portion (2a) is prevented from rotating by the pair of flat surfaces (2c)(2c), and a pair of stepped portions (2d)(2d) formed on the lower edge side by the recession of the pair of flat surfaces (2c)(2c) serve as a pair of pressure receiving portions (2aa)(2aa) of the fuel injector (2).

As shown in FIG. 3 or FIG. 4(A), in this engine, the pair of pressure receiving portions (2aa)(2aa) of the fuel injector (2) are simultaneously formed by recessing the pair of flat surfaces (2c)(2c) in the intermediate body portion (2a), so that the formation of the pair of pressure receiving portions (2aa)(2aa) is not time-consuming.

As shown in FIG. 3, in this engine, a fuel inlet (2f) is led out to the right from between the large diameter portion (2b) and the intermediate body portion (2a) of the fuel injector (2), and the outlet end of a fuel supply pipe led out from the common rail is connected to this fuel inlet (2f).
As shown in FIG. 3, in this engine, a right-facing connector (2g) is provided at the top of the fuel injector (2), and an end of a cable extending from an engine ECU (not shown) is connected to this connector (2g), so that a control signal is sent from the engine ECU to the fuel injector (2) and power is supplied to the fuel injector (2) from a battery (not shown).

As shown in FIG. 4(B), in this engine, the positioning protrusion (7c) protruding downward from the outer fitting portion (7b) of the sub-clamp (7) is sandwiched between the outer peripheral surface of the fuel injector (2) and the opposing end surface of the rocker arm bracket (3), positioning the sub-clamp (7).

As shown in FIG. 4(B), in this engine, when the fuel injector (2) is clamped, the positioning protrusion (7c) prevents the sub-clamp (7) from shifting in the radial direction along the pair of flat surfaces (2c)(2c) of the intermediate body (2a) shown in FIG. 3 or FIG. 4(A), and the pressure contact position between the pressing portion (6a) of the main clamp (6) and the pressure receiving portion (7a) of the sub-clamp (7) is fixed in a fixed position, suppressing variation in the magnitude and direction of the pressing force applied to the fuel injector (2).

As shown in FIG. 4(B), in this engine, the main clamp (6) is provided with a fulcrum portion (6b), a force point portion (6c), and an action point portion (6d).
As shown in FIG. 4(B), the fulcrum portion (6b) is provided on a first end side of the main clamp (6) away from the fuel injector (2), the force point portion (6c) is provided on a midpoint of the main clamp (6) into which the stud bolt (4) is fitted, and the action point portion (6d) is provided on a second end side of the main clamp (6) closer to the fuel injector (2).

As shown in Figure 4(B), in this engine, the fuel injector (2) can be strongly pressed and fixed in the injector insertion hole (1a) by the amplified pressing force from the application point (6d) due to the lever function of the main clamp (6), and the sealing performance of the fuel injector (2) in the injector insertion hole (1a) is also improved.

As shown in FIG. 4(B) , in this engine, the fulcrum portion (6b) has a first partial spherical portion (6ba) and a first spherical receiving hole (6bb) that fits with the first partial spherical portion (6ba), the first partial spherical portion (6ba) is fixed to the rocker arm bracket (3), and the first spherical receiving hole (6bb) is recessed upward from the bottom surface of the main clamp (6).
As shown in FIG. 4(B), the force point portion (6c) has a second partial spherical portion (6ca) and a second spherical receiving hole (6cb) that fits into the second partial spherical portion (6ca). The second partial spherical portion (6ca) is formed in the lower surface of a washer (4b) that is fitted onto the stud bolt (4). The second spherical receiving hole (6cb) is formed in the upper surface of a main clamp (6) that is fitted onto the stud bolt (4). The second partial spherical portion (6ca) of the washer (4b) is press-fitted into the second spherical receiving hole (6cb) of the main clamp (6) by the tightening force of a nut (4a) that is screwed onto the stud bolt (4).
As shown in FIG. 4(B), the pressing surface (6aa) of the pressing portion (6a) at the force point portion (6c) of the main clamp (6) which comes into contact with the flat pressure-receiving surface (7aa) of the pressure-receiving portion (7a) of the sub-clamp (7) is configured as a downwardly convex curved surface.

In this engine, the spherical support structure and convex curved support structure prevent concentrated stress from the edges on the contact surfaces of the main clamp (6) and sub clamp (7), increasing the durability of the clamp (5).

As shown in FIG. 5(A), the main clamp (6) has a base (6e) and a pair of pressing portions (6a) (6a) branching off from the base (6e) to the front and rear on the right side. The base (6e) has a first spherical receiving hole (6bb) on the left side of the lower surface. As shown in FIG. 5(A)(B), the base (6e) has a second spherical receiving hole (6cb) on the right side of the upper surface. As shown in FIG. 3, the second spherical receiving hole (6cb) is formed on the opening periphery of the bolt insertion hole (6ea) through which the stud bolt (4) is inserted.

As shown in FIG. 6(A), the sub-clamp (7) has a pair of pressure receiving parts (7a) that extend outward from the front and rear sides of the U-shaped outer fitting part (7b), and as shown in FIG. 6(B)(C), a pair of pressure receiving surfaces (7aa)(7aa) formed on the upper side of the pair of pressure receiving parts (7a) are positioned higher than the pressing surface (7ba) formed on the lower side of the outer fitting part (7b).

The main clamp (6) and the sub clamp (7) are both made of sintered steel.
The main clamp (6) and the secondary clamp (7) may be sintered, forged or cast products using iron-based metals other than steel or other metals.
The materials of the main clamp (6) and the secondary clamp (7) may be different. For example, the main clamp (6) may be made of a cast iron casting and the secondary clamp may be made of a sintered steel.

The procedure for pressing the fuel injector 2 shown in FIG. 3 or FIG. 4(B) with the clamp 5 is as follows.
As shown in FIG. 4(B), the rocker arm bracket (3) is pressed and fixed to the upper surface of the cylinder head (1) by the fastening force of a bracket fixing nut (4c) screwed onto a stud bolt (4) fixed to the cylinder head (1), and the fuel injector (2) is inserted into the injector insertion hole (1a) of the cylinder head (1).
Next, as shown in FIG. 3, sub-clamp (7) is slid laterally (S) diagonally downward from the left side of fuel injector (2) as shown by the arrow while the sub-clamp (7) is fitted onto intermediate body portion (2a), and as shown in FIG. 4(B), positioning protrusion (7c) of sub-clamp (7) is inserted between the outer circumferential surface of fuel injector (2) and the opposing end face of rocker arm bracket (3).

Next, as shown in FIG. 3, the main clamp (6) is fitted onto the stud bolt (4) and moved downward (D) along the stud bolt (4) until the pair of pressing portions (6a) (6a) of the main clamp (6) pass over the outer sides of both sides of the large diameter portion (2b) of the fuel injector (2).
Next, as shown in FIG. 4(A), the pair of pressing portions (6a) (6a) of the main clamp (6) are brought into contact with the pair of pressure-receiving portions (7a) (7a) of the sub-clamp (7), and the main clamp (6) is pressed downward via the washer (4b) by the fastening force of the nut (4a) screwed onto the stud bolt (4), which presses the pressure-receiving portion (2aa) of the fuel injector (2) via the sub-clamp (7) below the main clamp (6), thereby pressing and fixing the fuel injector (2) in the injector insertion hole (1a).

(1)...cylinder head, (1a)...injector insertion hole, (1b)...cylinder head cover, (2)...fuel injector, (2a)...middle body portion, (2aa)...pressure receiving portion, (2b)...large diameter portion, (2c)...flat surface, (2d)...step portion, (3)...rocker arm bracket, (4)...stud bolt, (4a)...nut, (4b)...washer, (5)...clamp, (6)...main clamp, (6a)...pressure portion, (6aa)...pressure surface, (6aD)...clearance dimension, (6b)...fulcrum portion, (6ba)...first partial spherical portion, (6bb)...first spherical receiving hole, (6c)...force point portion, (6ca)...second partial spherical portion, (6cb)...second spherical receiving hole, (6d)...point of action, (7)...secondary clamp, (7a)...pressure receiving part, (7aa)...pressure receiving surface, (7b)...outer fitting part, (7c)...positioning protrusion.

Claims (7)

A fuel injection engine comprising: a fuel injector (2) inserted into an injector insertion hole (1a) in a cylinder head (1); a rocker arm bracket (3) arranged within a cylinder head cover (1b); a stud bolt (4) for fixing the rocker arm bracket (3) to the cylinder head (1); and a clamp (5) arranged on an upper portion of the rocker arm bracket (3), the fuel injector (2) being pressed and fixed in the injector insertion hole (1a) by the pressing force of the clamp (5);
The fuel injector (2) is provided with a pressure receiving portion (2aa) in an intermediate body portion (2a) located in the middle of the axial length direction of the fuel injector (2),
The clamp (5) includes a main clamp (6) and a sub clamp (7), the sub clamp (7) is fitted onto the intermediate body portion (2a) of the fuel injector (2), and the main clamp (6) is disposed on the upper portion of the rocker arm bracket (3) and fitted onto the stud bolt (4);
1. A fuel injection engine, comprising: a main clamp (6) configured to press a pressure-receiving portion (2aa) of a fuel injector (2) via a sub-clamp (7) below the main clamp (6) by a tightening force of a nut (4a) screwed onto a stud bolt (4). 2. The fuel injected engine according to claim 1,
The fuel injector (2) is provided with a large diameter portion (2b) that is located above the secondary clamp (7) and that protrudes radially outward.
1. A fuel injected engine comprising: a main clamp (6) comprising a pair of pressing portions (6a) (6a) branched into two branches, a separation dimension (6aD) between the pair of pressing portions (6a) (6a) being formed to be larger than a diameter dimension (2bD) of a large diameter portion (2b) of a fuel injector (2), and configured such that when the main clamp (6) fitted around a stud bolt (4) is lowered (D) along the stud bolt (4) during clamping of the fuel injector (2), the pair of pressing portions (6a) (6a) of the main clamp (6) pass both sides of the large diameter portion (2b) of the fuel injector (2) and come into contact with the pair of pressure receiving portions (7a) (7a) of the sub clamp (7). 3. The fuel injected engine according to claim 2,
a pair of pressure-receiving portions (7a) (7a) of the sub-clamp (7) protrude outward from both sides of a U-shaped outer fitting portion (7b) that is fitted onto an intermediate body portion (2a) of the fuel injector (2), and are positioned radially outward from a large diameter portion (2b) of the fuel injector (2). 4. The fuel injected engine according to claim 3,
1. A fuel injection engine comprising: an intermediate body portion (2a) of a fuel injector (2) having a pair of flat surfaces (2c) (2c) on both sides thereof which are recessed toward a center thereof, a sub-clamp (7) fitted externally to the intermediate body portion (2a) being prevented from rotating by the pair of flat surfaces (2c) (2c), and a pair of stepped portions (2d) (2d) formed on a lower edge portion of the intermediate body portion (2a) by the recession of the pair of flat surfaces (2c) (2c) which serve as a pair of pressure-receiving portions (2aa) (2aa) of the fuel injector (2). A fuel injection type engine according to claim 3 or 4,
a positioning projection (7c) projecting downward from an outer fitting portion (7b) of the sub-clamp (7) is sandwiched between an outer peripheral surface of the fuel injector (2) and an end surface of the rocker arm bracket (3), thereby positioning the sub-clamp (7). 2. The fuel injected engine according to claim 1,
The main clamp (6) has a fulcrum portion (6b), a force point portion (6c), and an action point portion (6d),
a fulcrum portion (6b) provided on a first end side of the main clamp (6) away from the fuel injector (2), a force point portion (6c) provided on a midpoint of the main clamp (6) into which the stud bolt (4) is fitted, and an action point portion (6d) provided on a second end side of the main clamp (6) closer to the fuel injector (2). 7. A fuel injected engine according to claim 6,
The fulcrum portion (6b) has a first partial spherical portion (6ba) and a spherical receiving hole (6bb) that fits with the first partial spherical portion (6ba), the first partial spherical portion (6ba) is fixed to the rocker arm bracket (3), and the spherical receiving hole (6bb) is recessed upward from the bottom surface of the main clamp (6),
The force point portion (6c) has a second partial spherical portion (6ca) and a spherical receiving hole (6cb) that fits into the second partial spherical portion (6ca), the second partial spherical portion (6ca) is formed in the lower surface of a washer (4b) that is fitted onto the stud bolt (4), the spherical receiving hole (6cb) is formed in the upper surface of a main clamp (6) that is fitted onto the stud bolt (4), and the second partial spherical portion (6ca) of the washer (4b) is press-fitted into the spherical receiving hole (6cb) of the main clamp (6) by the tightening force of a nut (4a) that is screwed onto the stud bolt (4).
1. A fuel injected engine, comprising: a pressing surface (6aa) of a pressing portion (6a) at a force point portion (6c) of a main clamp (6) which is pressed against a flat pressure receiving surface (7aa) of a pressure receiving portion (7a) of a sub-clamp (7), the pressing surface (6aa) being configured as a downwardly convex curved surface.

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