Fuel injection engine

Abstract

The invention provides a fuel injection type engine which has a high degree of freedom in arrangement of components in a cylinder head cover and can maintain high fuel injection accuracy of a fuel injector (2). The fuel injector (2) has a pressure receiving portion (2aa) in an intermediate body portion (2a) located in the middle of the fuel injector (2) in the axial direction thereof, the jig (5) has a main jig (6) disposed on the upper portion of the rocker arm bracket (3) and fitted over the stud bolt (4), and a sub jig (7) fitted over the intermediate body portion (2a) of the fuel injector (2), and the pressure receiving portion (2aa) is pressed by the tightening force of a nut (4a) fastened to the stud bolt (4). The main jig (6) presses the pressure receiving section (2aa) of the fuel injector (2) via a sub-jig (7) on the lower side of the main jig (6).

Description

Technical Field

[0001] This invention relates to a fuel injection engine, and more specifically, to a fuel injection engine that allows for a high degree of freedom in the configuration of components within a narrow cylinder head cover and enables a high degree of accuracy in fuel injection. Background Technology

[0002] The inventor of this invention had previously proposed... Figure 1 and Figure 2 Fuel injection engine.

[0003] like Figure 1 or Figure 2 As shown, the fuel injection engine of the previously proposed Cases 1 and 2 is configured to have: a fuel injector (2) inserted into an injector insertion hole (1a) in the cylinder head (1); a rocker arm bracket (3) disposed in a cylinder head cover (not shown); a double-headed bolt (4) for fixing the rocker arm bracket (3) to the cylinder head (1); and a clamp (5) disposed on the upper side of the rocker arm bracket (3); the fuel injector (2) is pressed and fixed in the injector insertion hole (1a) by the pushing force of the clamp (5).

[0004] As prior art for this type of engine, there is patent document 1.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2021-110231 (see reference) Figure 1 ) Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] Problem Point 1: The narrow cylinder head cover reduces the freedom of component configuration.

[0010] exist Figure 1 In the previously proposed Case 1 shown, the fuel injector (2) is inserted into the injector insertion hole (1a). On the middle body part (2a) of the fuel injector (2) located on the lower side of the large diameter part (2b) of the fuel injector (2), the clamp (5) of the double fork structure is inserted by sliding laterally (S) along the radial direction of the middle body part (2a). The clamp (5) is then pressed by the tightening force of the head bolt (20), thereby pressing the pressure part (2aa) of the middle body part (2a).

[0011] Therefore, the bolt mounting portion (20a) of the head bolt (20) bulges out from the rocker arm bracket (3) toward the fuel injector (2), and the bolt mounting portion (20a) forms an obstruction, resulting in a reduced degree of freedom in the configuration of the fuel injector (2) and its surrounding components such as intake and exhaust valves, valve springs, and valve retainers, which are not shown, within the narrow cylinder head cover.

[0012] The invention in Patent Document 1 also has the same problem.

[0013] Problem Point 2: The fuel injection accuracy of the fuel injector (2) is reduced.

[0014] exist Figure 2 In the previously proposed Case 2 shown, the fuel injector (2) is inserted into the injector insertion hole (1a), and the clamp (5) externally fitted to the double-ended bolt (4) descends (D) along the double-ended bolt (4). The clamp (5) is pushed by the tightening force of the nut (4a) that is threaded into the double-ended bolt (4). However, when the clamp (5) of the double-fork structure descends (D), the clamp (5) touches the large diameter part (2b) of the fuel injector (2) located on the upper side of the middle main body (2a), thereby restricting the descent of the clamp (5) (D). Therefore, a pressure part (2aa) is formed on the large diameter part (2b), and the clamp (5) pushes the pressure part (2aa).

[0015] Therefore, the fuel injector (2) is pushed at a higher position, and the precision components inside the fuel injector (2) may be deformed due to the pressure, thus reducing the fuel injection accuracy of the fuel injector (2).

[0016] The objective of this invention is to provide a fuel injection engine that allows for a high degree of freedom in the arrangement of components within a narrow cylinder head cover and can maintain a high degree of fuel injection accuracy.

[0017] Technical means to solve the problem

[0018] The main structure of the invention in this application is as follows.

[0019] like Figure 3 As illustrated, the fuel injection engine is configured to have: a fuel injector (2) inserted into an injector insertion hole (1a) in the cylinder head (1); and a fuel injector (2) disposed in the cylinder head (1). Figure 4 (B) shows a rocker arm bracket (3) inside the cylinder head cover (1b); a double-ended bolt (4) for fixing the rocker arm bracket (3) to the cylinder head (1); and a clamp (5) disposed on the upper side of the rocker arm bracket (3); the fuel injector (2) is pressed and fixed in the injector insertion hole (1a) by the pushing force of the clamp (5), characterized in that, like Figure 3As illustrated, the fuel injector (2) has a pressure-bearing portion (2aa) in the middle body portion (2a) located in the middle of the axial length direction of the fuel injector (2). like Figure 3 As illustrated, the clamp (5) has a main clamp (6) and a secondary clamp (7). The secondary clamp (7) is externally embedded in the middle main body (2a) of the fuel injector (2), and the main clamp (6) is disposed on the upper part of the rocker arm bracket (3) and externally embedded in the double-ended bolt (4). like Figure 3 As illustrated, the main clamp (6) is used to push the pressure part (2aa) of the fuel injector (2) by the tightening force of the nut (4a) that is threaded into the double-ended bolt (4) via the auxiliary clamp (7) on the lower side of the main clamp (6).

[0020] Invention Effects

[0021] The invention described in this application has the following effects.

[0022] Effect 1: The freedom of component configuration within the narrow cylinder head cover (1b) is increased.

[0023] like Figure 3 As illustrated, in this invention, since the double-ended bolt (4) fixing the rocker arm bracket (3) is also used as the mounting bolt for the main clamp (6), unlike the inventions of the previously proposed Case 1 or Patent Document 1, it is not necessary to use the double-ended bolt (4) fixing the rocker arm bracket (3) as the mounting bolt for the main clamp (6). Figure 1 As illustrated, by making the bolt mounting portion (20a) of the head bolt (20) bulge out from the rocker arm bracket (3) toward the fuel injector (2), it is possible to... Figure 4 (B) The fuel injector (2) and its surrounding intake and exhaust valves, valve springs, valve retainers and other components within the narrow cylinder head cover (1b) shown in the example have a higher degree of freedom in configuration.

[0024] Effect 2 can maintain the fuel injection accuracy of the fuel injector (2) to a high degree.

[0025] like Figure 3 As illustrated, in this invention, since the auxiliary clamp (7) is externally embedded in the middle main body (2a) of the fuel injector (2), the main clamp (6) is pushed by the auxiliary clamp (7) below the main clamp (6) through the tightening force of the nut (4a) threaded into the double-ended bolt (4) to the pressure portion (2aa) of the middle main body (2a) of the fuel injector (2), thus... Figure 2 Unlike the previously proposed Case 2, the fuel injector (2) is pushed at a lower position, and the precision components inside the fuel injector (2) are not easily deformed by bending, thus maintaining the fuel injection accuracy of the fuel injector (2) to a higher degree.

[0026] Effect 3 can repair jigs at a low cost (5).

[0027] like Figure 3 As illustrated, in this invention, since the fixture (5) is composed of a main fixture (6) and a secondary fixture (7), in the event of early wear of the secondary fixture (7), the fixture (5) can be repaired at a low cost by simply replacing the secondary fixture (7). Attached Figure Description

[0028] Figure 1 This is a three-dimensional diagram of the main part of the previously proposed Case 1.

[0029] Figure 2 This is a three-dimensional diagram of the main part of the previously proposed Case 2.

[0030] Figure 3 This is a perspective view of the main parts of an embodiment of the present invention.

[0031] Figure 4 These are diagrams illustrating the main parts of embodiments of the present invention. Figure 4 (A) is a top view. Figure 4 (B) is the front view.

[0032] Figure 5 This is a diagram illustrating the main clamp used in embodiments of the present invention. Figure 5 (A) is a top view. Figure 5 (B) is the front view. Figure 5 (C) is Figure 5 (A) is the view in direction C.

[0033] Figure 6 This is a diagram illustrating the auxiliary clamp used in embodiments of the present invention. Figure 6 (A) is a top view. Figure 6 (B) is the front view. Figure 6 (C) is Figure 6 (A) is the view in direction C. Detailed Implementation

[0034] Figure 1 and Figure 2 This is a previously proposed case. Figures 3 to 5 This diagram illustrates a fuel injection engine according to an embodiment of the present invention. In this embodiment, a common rail, multi-valve, vertical inline multi-cylinder diesel engine will be described.

[0035] The engine has a plurality of cylinders arranged in the direction of crankshaft mounting (not shown).

[0036] In the previously proposed cases or embodiments of the present invention, the crankshaft mounting direction is taken as the front-rear direction, one side of the front-rear direction, such as the side where the engine cooling fan or radiator is located, is taken as the front; the other side, such as the side where the flywheel is located, is taken as the rear; the width direction of the engine is taken as the left-right direction, with the left side of the observer facing forward from the position of the engine as the left and the right side as the right, and the height direction of the engine as the up-down direction, which is illustrated and explained.

[0037] This engine has an intake device, a fuel supply device, and an exhaust device.

[0038] Although not shown in the figure, the intake and exhaust system includes intake and exhaust ports, intake and exhaust valves, and valve actuation devices.

[0039] The intake and exhaust ports (not shown) are formed in Figure 4 (B) shows that the intake and exhaust valves are four-valve intake and exhaust valves with two intake valves and two exhaust valves in each cylinder, and are therefore arranged around the fuel injector (2).

[0040] The valve actuator not shown is an overhead valve type valve actuator with a valve drive camshaft, pushrod, and rocker arm.

[0041] The rocker arm pivot, not shown, is supported by... Figure 4 (A) shows the rocker arm bracket (3) supporting the rocker arm pivot (3a).

[0042] The fuel supply system includes an engine ECU (engine electronic control unit) not shown, a fuel supply pump, a common rail, and a fuel supply line.

[0043] The fuel supply device has units located in each cylinder. Figure 3 The fuel injector (2) shown in the diagram is pressurized in the common rail and the liquid fuel (light oil) is pumped from the fuel supply pipe to the fuel injector (2). Through electronic control, the fuel injection valve of the fuel injector (2) opens at a specified time and injects a specified amount of fuel into each cylinder at a specified time.

[0044] like Figure 4 As shown in (B), the rocker arm bracket (3) is mounted and fixed on the upper surface of the cylinder head (1) and housed in the cylinder head cover (1b) mounted and fixed on the upper surface of the cylinder head (1).

[0045] like Figure 4As shown in (B), in this engine, a double-ended bolt (4) is screwed in and fixed to the cylinder head (1). The double-ended bolt (4) stands up from the upper surface of the cylinder head (1). The rocker arm bracket (3) is externally embedded in the double-ended bolt (4). The rocker arm bracket (3) is pressed and fixed to the upper surface of the cylinder head (1) by the tightening force of the bracket fixing nut (4c) that is threaded with the middle part of the double-ended bolt (4).

[0046] like Figure 4 As shown in (B), the top portion of the fuel injector (2) is inserted into the injector insertion hole (1a) of the cylinder head (1). A copper annular washer (1c) is disposed between the downward injector pressing surface (2e) of the top portion of the fuel injector (2) and the inner end face (1aa) of the injector insertion hole (1a). By applying the pressing force to the fuel injector (2), the injector pressing surface (2e) is pressed and fixed to the inner end face (1aa) of the injector insertion hole (1a) via the annular washer (1c). The injector pressing surface (2e) and the inner end face (1aa) of the injector insertion hole (1a) are sealed to each other by the annular washer (1c) that is pressed between them.

[0047] like Figure 4 As shown in (B), the inner circumferential surface of the injector insertion hole (1a) and the outer circumferential surface of the fuel injector (2) are sealed to each other by a pair of upper and lower O-rings (1d), (1d).

[0048] like Figure 3 As shown, the engine is configured to have: a fuel injector (2) inserted into an injector insertion hole (1a) in the cylinder head (1); and a fuel injector (2) disposed in the cylinder head (1). Figure 4 (B) shows the rocker arm bracket (3) inside the cylinder head cover (1b); as Figure 3 The double-headed bolts (4) shown fix the rocker arm bracket (3) to the cylinder head (1); and the clamp (5) is arranged on the upper side of the rocker arm bracket (3); the fuel injector (2) is pressed and fixed in the injector insertion hole (1a) by the pushing force of the clamp (5).

[0049] like Figure 3 As shown, the fuel injector (2) has a pressure-bearing part (2aa) in the middle body part (2a) located in the middle of the axial length direction of the fuel injector (2).

[0050] like Figure 3 As shown, the clamp (5) has a main clamp (6) and a secondary clamp (7). The secondary clamp (7) is externally embedded in the middle main body (2a) of the fuel injector (2), and the main clamp (6) is disposed on the upper side of the rocker arm bracket (3) and externally embedded in the double-headed bolt (4).

[0051] like Figure 3As shown, in this engine, the main clamp (6) pushes the pressure portion (2aa) of the middle main body (2a) of the fuel injector (2) through the secondary clamp (7) below the main clamp (6) by the tightening force of the nut (4a) that is threaded into the double-ended bolt (4).

[0052] like Figure 3 As shown, in this engine, since the double-ended bolt (4) that fixes the rocker arm bracket (3) is also used as the mounting bolt for the main clamp (6), unlike the invention in Case 1 or Patent Document 1, it is not necessary to use the same method as in the previous invention. Figure 1 By making the bolt mounting part (20a) bulge out from the rocker arm bracket (3) toward the fuel injector (2) as shown, it is possible to... Figure 4 The fuel injector (2) and its surrounding intake and exhaust valves, valve springs, valve retainers, and other components within the narrow cylinder head cover (1b) shown in (B) have a higher degree of freedom in configuration.

[0053] like Figure 3 As shown, in this engine, the auxiliary clamp (7) is externally embedded in the middle main body (2a) of the fuel injector (2). By utilizing the tightening force of the nut (4a) that is threaded into the double-ended bolt (4), the main clamp (6) pushes the pressure part (2aa) of the fuel injector (2) through the auxiliary clamp (7) on the lower side of the main clamp (6). Therefore, unlike the previously proposed Case 2, the fuel injector (2) is pushed at a lower position, and the precision parts inside the fuel injector (2) are not easily deformed by bending, thus maintaining the fuel injection accuracy of the fuel injector (2) at a higher level.

[0054] like Figure 3 As shown, in this engine, since the clamp (5) is composed of a main clamp (6) and a secondary clamp (7), in the case of early wear of the secondary clamp (7), the clamp (5) can be repaired at a low cost by simply replacing the secondary clamp (7).

[0055] like Figure 3 As shown, in this engine, the fuel injector (2) has a large-diameter portion (2b) that protrudes radially outward on the side above the sub-clamp (7).

[0056] like Figure 5 As shown in (A), the main clamp (6) has a pair of bifurcated pressing parts (6a) and (6a), and the spacing (6aD) between the pair of pressing parts (6a) and (6a) is formed to be larger than the diameter (2bD) of the large diameter part (2b) of the fuel injector (2).

[0057] like Figure 3As shown, in this engine, when clamping the fuel injector (2), when the main clamp (6) externally embedded in the double-ended bolt (4) is lowered (D) along the double-ended bolt (4), a pair of pushing parts (6a) of the main clamp (6) abut against a pair of pressing parts (7a) of the auxiliary clamp (7) on both sides of the large diameter part (2b) of the fuel injector (2).

[0058] like Figure 3 As shown, in this engine, even if there is a large diameter section (2b) in the fuel injector (2), the large diameter section (2b) does not get in the way. The main clamp (6) externally embedded in the double-ended bolt (4) can be lowered (D) along the double-ended bolt (4) and abut against the pressure part (7a) of the auxiliary clamp (7). By simply tightening the nut (4a) that is threaded into the double-ended bolt (4), the main clamp (6) can push the pressure part (2aa) of the fuel injector (2) through the auxiliary clamp (7) below it, thereby making it easy to perform the clamping operation of the fuel injector (2).

[0059] like Figure 3 As shown, in this engine, the pressure-bearing part (7a) of the sub-clamp (7) protrudes outward from both sides of the "ko"-shaped outer part (7b) of the middle main body part (2a) of the fuel injector (2), and is configured to be further radially outward than the large diameter part (2b) of the fuel injector (2).

[0060] In this engine, even if there is a large diameter section (2b) in the fuel injector (2), the interference between the large diameter section (2b) and the main clamp (6) during the clamping operation of the fuel injector (2) can be avoided simply by making the pressure part (7a) of the sub-clamp (7) protrude outward from both sides. This allows the pushing part (6a) of the main clamp (6) to pass through both sides of the large diameter section (2b) of the fuel injector (2). Therefore, there is no need to change the structure of the fuel injector (2) by reducing the diameter of the large diameter section (2b) of the fuel injector (2), and the fuel injection accuracy of the fuel injector (2) can be maintained at a high level.

[0061] like Figure 3 or Figure 4 As shown in (A), in this engine, the middle main body (2a) of the fuel injector (2) has a pair of flat surfaces (2c) and (2c) that are recessed toward the center on both sides. The auxiliary clamp (7) that is embedded in the middle main body (2a) is prevented from rotating by the pair of flat surfaces (2c) and (2c). A pair of stepped portions (2d) and (2d) formed on the lower edge side due to the recess of the pair of flat surfaces (2c) and (2c) form a pair of pressure portions (2aa) and (2aa) of the fuel injector (2).

[0062] like Figure 3 or Figure 4As shown in (A), in this engine, due to the indentation of a pair of flat surfaces (2c) on the middle main body (2a), a pair of pressure-bearing parts (2aa) and (2aa) of the fuel injector (2) are also formed at the same time, so there is no need to painstakingly form a pair of pressure-bearing parts (2aa) and (2aa).

[0063] like Figure 3 As shown, in this engine, a fuel inlet (2f) extends to the right from between the large-diameter portion (2b) of the fuel injector (2) and the intermediate main body portion (2a), and the outlet end of the fuel supply pipe extending from the common rail is connected to the fuel inlet (2f).

[0064] like Figure 3 As shown, in this engine, a right-facing connector (2g) is provided at the top of the fuel injector (2). The connector (2g) is connected to the output end of a cable from the engine ECU (not shown), which sends control signals from the engine ECU to the fuel injector (2) and supplies power to the fuel injector (2) from a battery (not shown).

[0065] like Figure 4 As shown in (B), in this engine, a positioning protrusion (7c) protruding downward from the outer part (7b) of the sub-clamp (7) is clamped between the outer peripheral surface of the fuel injector (2) and the opposing end face of the rocker arm bracket (3), and the sub-clamp (7) is positioned.

[0066] like Figure 4 As shown in (B), in this engine, when the fuel injector (2) is clamped, the positioning protrusion (7c) is used to eliminate the flow along the fuel injector. Figure 3 or Figure 4 The positional offset of the radial sub-clamps (7) of the pair of flat surfaces (2c) of the intermediate main body (2a) shown in (A) causes the pressing position of the pressing part (6a) of the main clamp (6) and the pressing part (7a) of the sub-clamp (7) to be fixed in a fixed position, thereby suppressing the deviation in magnitude and direction of the pushing force applied to the fuel injector (2).

[0067] like Figure 4 As shown in (B), in this engine, the main clamp (6) has a fulcrum (6b), a force point (6c), and an action point (6d).

[0068] like Figure 4 As shown in (B), the fulcrum (6b) is located on the first end side of the main clamp (6) away from the fuel injector (2), the force point (6c) is located in the middle part of the main clamp (6) with the double-headed bolt (4) embedded in it, and the action point (6d) is located on the second end side of the main clamp (6) near the fuel injector (2).

[0069] like Figure 4As shown in (B), in this engine, the increased thrust generated from the point of action (6d) by the lever function of the main clamp (6) can forcefully push and fix the fuel injector (2) in the injector insertion hole (1a), and also improve the sealing of the fuel injector (2) in the injector insertion hole (1a).

[0070] like Figure 4 As shown in (B), in this engine, the pivot part (6b) has a first spherical part (6ba) and a first spherical receiving hole (6bb) that fits into the first spherical part (6ba). The first spherical part (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).

[0071] like Figure 4 As shown in (B), the force point (6c) has a second spherical part (6ca) and a second spherical receiving hole (6cb) that engages with the second spherical part (6ca). The second spherical part (6ca) is formed on the lower surface of the washer (4b) that is externally fitted into the double-ended bolt (4), and the second spherical receiving hole (6cb) is formed on the upper surface of the main clamp (6) that is externally fitted into the double-ended bolt (4). By utilizing the tightening force of the nut (4a) that is threadedly engaged with the double-ended bolt (4), the second spherical part (6ca) of the washer (4b) is pushed and fitted into the second spherical receiving hole (6cb) of the main clamp (6).

[0072] like Figure 4 As shown in (B), the pressing surface (6aa) of the pressing part (6a) that abuts against the flat pressing surface (7aa) of the pressing part (7aa) of the sub-clamp (7) is composed of a downwardly convex curved surface. In the main clamp (6), the pressing part (6a) is located at the force point (6c).

[0073] In this engine, through the spherical bearing structure and the convex curved bearing structure, stress concentration caused by the edge is not easily generated on each pressing surface of the main clamp (6) and the auxiliary clamp (7), which also improves the durability of the clamp (5).

[0074] like Figure 5 As shown in (A), the main clamp (6) has a base (6e) and a pair of pushing parts (6a), (6b) branching from the base (6e) to the right. A first spherical receiving hole (6bb) is located on the lower left surface of the base (6e). Figure 5 As shown in (A) and (B), a second spherical receiving hole (6cb) is provided on the upper right surface of the base (6e), as... Figure 3 As shown, the second spherical receiving hole (6cb) is formed at the periphery of the opening of the bolt insertion hole (6ea) through which the double-ended bolt (4) is inserted.

[0075] like Figure 6As shown in (A), the sub-clamp (7) has a pair of pressure-bearing parts (7a) extending outward from the front and rear sides of the "ko"-shaped insert (7b), as... Figure 6 As shown in (B) and (C), a pair of pressure surfaces (7aa) formed on the upper side of a pair of pressure portions (7a) are positioned at a higher position than the pushing surface (7ba) formed on the lower side of the outer portion (7b).

[0076] Both the main clamp (6) and the auxiliary clamp (7) are made of sintered steel.

[0077] The main clamp (6) and the auxiliary clamp (7) can be made of ferrous metals other than steel or other metals, such as sintered products, forged products, or castings.

[0078] The main clamp (6) and the auxiliary clamp (7) can be made of different materials. For example, the main clamp (6) can be made of cast iron, while the auxiliary clamp can be made of sintered steel.

[0079] Figure 3 or Figure 4 The pressing sequence of the clamp (5) based on the fuel injector (2) shown in (B) is as follows.

[0080] like Figure 4 As shown in (B), the rocker arm bracket (3) is pressed and fixed on the upper surface of the cylinder head (1) by the tightening force of the bracket fixing nut (4c) that is fixed to the cylinder head (1) and threaded into the double-ended bolt (4), and the fuel injector (2) is inserted into the injector insertion hole (1a) of the cylinder head (1).

[0081] Next, as Figure 3 As shown, the auxiliary clamp (7) slides laterally (S) diagonally downward from the left side of the fuel injector (2) as indicated by the arrow, and the auxiliary clamp (7) is externally fitted into the middle main body (2a), as shown. Figure 4 As shown in (B), the positioning protrusion (7c) of the sub-clamp (7) is inserted between the outer peripheral surface of the fuel injector (2) and the opposing end face of the rocker arm bracket (3).

[0082] Next, as Figure 3 As shown, the main clamp (6) is externally embedded in the double-ended bolt (4) and lowered (D) along the double-ended bolt (4) so ​​that the pair of pushing parts (6a) of the main clamp (6) pass on both sides of the outer side of the large diameter part (2b) of the fuel injector (2).

[0083] Next, as Figure 4As shown in (A), the pair of pushing parts (6a), (6a) of the main clamp (6) abut against the pair of pressing parts (7a), (7a) of the auxiliary clamp (7). Using the tightening force of the nut (4a) that is threaded into the double-ended bolt (4), the main clamp (6) is pushed down through the washer (4b). The pressing part (2aa) of the fuel injector (2) is pushed down through the auxiliary clamp (7) on the lower side of the main clamp (6), and the fuel injector (2) is pressed and fixed in the injector insertion hole (1a).

[0084] Explanation of reference numerals in the attached figures

[0085] (1): Cylinder head, (1a): Injector insertion hole, (1b): Cylinder head cover, (2): Fuel injector, (2a): Intermediate main body, (2aa): Pressure-bearing part, (2b): Large diameter part, (2c): Flat surface, (2d): Stepped part, (3): Rocker arm bracket, (4): Double-ended bolt, (4a): Nut, (4b): Washer, (5): Fixture, (6): Main fixture, (6a): Pushing part, (6aa): Pushing surface, (6aD): Spacing dimension, (6b): Support point part, (6ba): First spherical part, (6bb): First spherical receiving hole, (6c): Force point part, (6ca): Second spherical part, (6cb): Second spherical receiving hole, (6d): Action point part, (7): Sub-fixture, (7aa): Pressure-bearing part, (7aa): Pressure-bearing surface, (7b): Outer part, (7c): Positioning protrusion.

Claims

1. 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) disposed within a cylinder head cover (1b); a double-ended bolt (4) for fixing the rocker arm bracket (3) to the cylinder head (1); and a clamp (5) disposed on the upper part of the rocker arm bracket (3); wherein the fuel injector (2) is pressed and fixed within the injector insertion hole (1a) by means of the pushing force of the clamp (5), characterized in that, The fuel injector (2) has a pressure-bearing part (2aa) in the middle body part (2a) located in the middle of the axial length direction of the fuel injector (2). The clamp (5) has a main clamp (6) and a secondary clamp (7). The secondary clamp (7) is externally embedded in the middle main body (2a) of the fuel injector (2). The main clamp (6) is disposed on the upper part of the rocker arm bracket (3) and externally embedded in the double-headed bolt (4). Using the tightening force of the nut (4a) that is threaded into the double-ended bolt (4), the main clamp (6) pushes the pressure part (2aa) of the fuel injector (2) via the auxiliary clamp (7) on the lower side of the main clamp (6).

2. The fuel injection engine according to claim 1, characterized in that, The fuel injector (2) has a large-diameter portion (2b) that protrudes radially outward at a position higher than the sub-clamp (7). The main clamp (6) has a pair of pushing parts (6a) and (6a) that are branched into a bifurcated shape. The spacing (6aD) between the pair of pushing parts (6a) and (6a) is larger than the diameter (2bD) of the large diameter part (2b) of the fuel injector (2). When the fuel injector (2) is clamped, the main clamp (6) that is externally embedded in the double-ended bolt (4) is lowered (D) along the double-ended bolt (4). The pair of pushing parts (6a) and (6a) of the main clamp (6) abut against the pair of pressure-bearing parts (7a) and (7a) of the auxiliary clamp (7) on both sides of the large diameter part (2b) of the fuel injector (2).

3. The fuel injection engine according to claim 2, characterized in that, The pair of pressure-bearing parts (7a) of the auxiliary clamp (7) protrude outward from both sides of the "ko"-shaped outer part (7b) of the middle main body part (2a) of the fuel injector (2), and are arranged to be further radially outward than the large diameter part (2b) of the fuel injector (2).

4. The fuel injection engine according to claim 3, characterized in that, The middle body part (2a) of the fuel injector (2) has a pair of flat surfaces (2c) and (2c) recessed towards the center on both sides of the middle body part (2a). The auxiliary clamp (7) embedded in the middle body part (2a) is prevented from rotating by the pair of flat surfaces (2c) and (2c). Due to the recess of the pair of flat surfaces (2c) and (2c), a pair of stepped parts (2d) and (2d) are formed at the lower edge of the pair of flat surfaces (2c) and (2c), forming a pair of pressure-bearing parts (2aa) and (2aa) of the fuel injector (2).

5. The fuel injection engine according to claim 3 or 4, characterized in that, The positioning protrusion (7c) protruding downward from the outer part (7b) of the sub-clamp (7) is clamped between the outer peripheral surface of the fuel injector (2) and the end face of the rocker arm bracket (3), thereby positioning the sub-clamp (7).

6. The fuel injection engine according to claim 1, characterized in that, The main clamp (6) has a fulcrum (6b), a force point (6c), and an action point (6d). The fulcrum (6b) is located on the first end side of the main clamp (6) away from the fuel injector (2), the force point (6c) is located in the middle part of the main clamp (6) with the double-headed bolt (4) embedded in it, and the action point (6d) is located on the second end side of the main clamp (6) near the fuel injector (2).

7. The fuel injection engine according to claim 6, characterized in that, The fulcrum (6b) has a first spherical part (6ba) and a spherical receiving hole (6bb) that fits into the first spherical part (6ba). The first spherical part (6ba) is fixed to the rocker arm bracket (3). The spherical receiving hole (6bb) is recessed upward from the bottom surface of the main clamp (6). The force point (6c) has a second spherical part (6ca) and a spherical receiving hole (6cb) that fits into the second spherical part (6ca). The second spherical part (6ca) is formed on the lower surface of the washer (4b) that is externally fitted into the double-ended bolt (4). The spherical receiving hole (6cb) is formed on the upper surface of the main clamp (6) that is externally fitted into the double-ended bolt (4). By using the tightening force of the nut (4a) that is threaded into the double-ended bolt (4), the second spherical part (6ca) of the washer (4b) is pushed and fitted into the spherical receiving hole (6cb) of the main clamp (6). The pressing surface (6aa) of the pressing part (6aa) and the pressing part (7aa) of the auxiliary clamp (7) are pressed together by a flat pressing surface (7aa). The pressing surface (6aa) is composed of a downwardly convex curved surface. In the main clamp (6), the pressing part (6aa) is located at the force point (6c).

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