JP2015175256A - fuel injection valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize a deformation and a step at an O-ring in its axial direction and prevent its damage.SOLUTION: A protrusion is formed at an inner diameter side of a back-up ring 18 to prevent flash of the inner diameter side of an O-ring 17 so as to minimize a deformation and a step in its axial direction in addition to a deformation of the O-ring 17 in its radial direction as well for preventing the O-ring 17 from being damaged. In order to prevent flash at the outer diameter part of the O-ring 17 and minimize its deformation in its axial direction, a plate thickness of the back-up ring 18 in its axial direction is changed and a deformation of the back-up ring 18 itself when the O-ring 17 is deformed at its outer diameter and in its axial direction, i.e. an elastic coefficient of the back-up ring 18 itself is decreased and damage of the O-ring 17 is restricted. With the foregoing, when fuel pressure acts against the outer diameter part of the O-ring 17, the back-up ring 18 is deformed in its axial direction to bear the load applied to the outer diameter part of the O-ring 17 and prevent damage of the O-ring 17.

Description

  The present invention relates to a fuel seal structure of a fuel injection valve for an automobile internal combustion engine.

  In an internal combustion engine such as an automobile, an electromagnetic fuel injection valve driven by an electric signal from an engine control unit is widely used.

  This type of fuel injection valve includes a so-called port injection that is attached to an intake pipe and indirectly injects fuel into the combustion chamber, and a direct injection type that directly injects fuel into the combustion chamber. Exists.

  In the latter direct injection type, high pressure fuel is supplied from the fuel pipe, the fuel is sealed by the 0-ring as a seal member at the connection between the fuel pipe and the fuel injection valve, and the backup ring that supports the 0-ring, and the fuel leaks out. It prevents that. The backup ring absorbs the axial deviation between the mounting hole of the cylinder head and the fuel pipe and always seals the connection between the fuel pipe and the fuel injection valve and reliably prevents the O-ring from sticking out without damaging the ring. (See Patent Document 1).

JP 2011-196260 A

  When a backup ring is incorporated between the fuel pipe and the fuel injection valve, if a gap is formed between the pair of end faces of the backup ring, a part of the 0 ring is formed when the fuel pressure acts on the 0 ring. If the O-ring is caught by entering the gap, the O-ring may be damaged, and fuel may leak out from the connection between the fuel pipe and the fuel injection valve. In order to prevent damage to the 0-ring, it is important to minimize the deformation and step in the axial direction in addition to the radial deformation of the 0-ring. In the fuel injection valve described in Patent Document 1, a double ring is formed in the radial direction of the backup ring, an elastic member is used on the fuel pipe side, and a hard member is used on the fuel injection valve side. By absorbing the shaft misalignment between the mounting hole and the fuel pipe and eliminating the gap between the inner and outer diameters of the backup ring, the 0 ring is prevented from being caught. In this case, since the fuel injection valve side of the backup ring is a hard member, it is unlikely that the 0-ring inner diameter side enters the gap, but the fuel pipe side of the backup ring uses an elastic member, so the fuel of the backup ring There is a risk of deformation or a step in the axial direction from the injection valve side.

  It is an object of the present invention to minimize the deformation and step in the axial direction of the 0 ring and prevent the 0 ring from being damaged.

    In the present invention, in order to prevent damage to the 0 ring, in addition to the deformation in the radial direction of the 0 ring, the back-up ring shape is configured so as to minimize the deformation and the step in the axial direction. In order to prevent the protrusion of the protrusion, a protrusion is formed on the inner diameter side of the backup ring.

  On the other hand, the elastic modulus of the backup ring itself is reduced by changing the plate thickness in the axial direction of the backup ring in order to prevent the 0 ring outer diameter side from protruding. As a result, when the fuel pressure acts on the 0-ring outer diameter portion, the backup ring is deformed in the axial direction to share the load on the 0-ring outer diameter portion, thereby preventing the 0-ring from being damaged.

  According to the present invention, in the fuel injection valve having the backup ring provided with the cut, the 0 ring is prevented from being damaged due to the engagement of the 0 ring, and the fuel pipe and the fuel injection valve are prevented from being damaged. It is possible to prevent the fuel from leaking out.

It is an external view which shows the structure of the 1st Example of the fuel injection valve which concerns on this invention. It is an attachment figure of the 1st example of the fuel injection valve concerning the present invention. It is a schematic diagram which shows the example which mounted the fuel injection valve of 1st Example in the cylinder injection type internal combustion engine.

  Examples according to the present invention will be described below.

  FIG. 1 is a cross-sectional view showing a first embodiment of a fuel injection valve 100 according to the present invention. The lower end portion of the nozzle 5 is provided with a plunger 4 of the valve body, a rod guide 14 and PR guide 12 guided by the outer peripheral surface thereof, and an orifice cup 7 which is a seating portion of the valve body. The part is fixed to the nozzle 5 by a method such as welding.

The nozzle 5, the core 2 of the inner fixed iron core, and the housing 3 of the cylindrical member are coupled by a method such as welding, and the rod guide 14, the zero spring 11, and the movable iron core anchor 13 are mounted inside the nozzle 5. A coil is mounted inside the housing 3 of the cylindrical member, and a spring 8, an adjuster pin 9, and a filter 10 are mounted inside the core 2 of the inner fixed iron core. An adjuster pin 9 is fixed inside the core 2 of the inner fixed iron core, and a spring 8 is provided in a compressed state with the lower end portion of the adjuster pin 9 as a fixed end. The spring force is transmitted to the plunger 4 of the valve body, the movable core anchor 13, the zero spring 11 and the rod guide 14, and the plunger 4 of the valve body is pressed against the orifice cup 7 valve seat. In this state, since the fuel passage is closed, the fuel stays in the fuel injection valve 100 from the fuel pipe, and fuel injection from the plurality of fuel injection holes is not performed. In addition, a magnetic circuit that makes a circuit around the coil 6 is constituted by the housing 3, the movable core anchor 13, and the inner fixed core 2.

  When the injection pulse is turned on, a current flows through the coil 6, the movable iron core 13 is attracted to the core 2 of the inner fixed iron core by electromagnetic force, and the plunger rod of the valve body 4 is pushed up upstream. At this time, a gap is formed between the upper end surface of the anchor 13 and the lower end surface of the core 2 of the inner fixed iron core. At this time, a gap is formed between the upper end surface of the plunger 4 of the valve body and the lower end surface of the core 2 of the inner fixed iron core. In this open state, a gap is formed between the plunger 4 of the valve body and the valve seat, so that the fuel passage is opened and fuel is injected from the plurality of fuel injection holes.

  When the injection pulse is turned off, no current flows through the coil 6 and the electromagnetic force disappears. Therefore, the valve element 4 returns to the closed state by the spring force, and the fuel injection is finished. As described above, the operation of the fuel injection valve 100 is to switch the position of the plunger 4 of the valve body between the valve open state and the valve closed state according to the injection pulse, and to control the fuel supply amount. Further, by injecting from a plurality of fuel injection holes, a fuel spray having a small fuel particle size, that is, good atomization is formed.

  FIG. 2 is an attachment diagram on the fuel pipe side showing a first embodiment of the fuel injection valve 100 according to the present invention. The upper part of the fuel injection valve 100 is provided with a 0 ring 17 and a backup ring 18 inside the fuel pipe 19 to seal the fuel supplied from the fuel pipe side. In the present invention, in order to prevent damage to the 0 ring, in addition to the deformation in the radial direction of the 0 ring, the back-up ring shape is configured so as to minimize the deformation and the step in the axial direction. In order to prevent the protrusion of the protrusion, a protrusion is formed on the inner diameter side of the backup ring.

  On the other hand, in order to prevent the 0 ring outer diameter side from protruding and minimize axial deformation, the plate thickness is changed in the axial direction of the backup ring, and the O ring is deformed in the outer diameter and axial direction. The backup ring itself is deformed, that is, the elastic modulus of the backup ring itself is reduced, and damage to the zero ring is suppressed. As a result, when the fuel pressure acts on the 0-ring outer diameter portion, the backup ring is deformed in the axial direction to share the load on the 0-ring outer diameter portion, thereby preventing the 0-ring from being damaged.

  Next, an example in which the fuel injection valve 100 is attached to the direct injection internal combustion engine 101 will be described. FIG. 3 shows an example in which the fuel injection valve 100 is attached to a direct injection internal combustion engine 101, where 102 is a combustion chamber, 103 is a piston, 104 is a cavity formed in the piston, 105 is a cylinder, and 106 is a cylinder head. 107 is an intake valve device for opening and closing the intake port 108, 109 is an exhaust valve device, and 110 is an ignition device. An intake passage 111 has a central partition that separates the intake port 108 and communicates with the upstream side.

1 Mold 2 Core 3 Housing 4 Plunger 5 Nozzle 6 Coil 7 Orifice Cup 8 Spring 9 Adjuster Pin 10 Filter 11 Zero Spring 12 PR Guide 13 Anchor 14 Rod Guide 15 Tip Seal 16 Connector 17 0 Ring 18 Backup Ring 19 Fuel Pipe 101 In-Cylinder Injection type internal combustion engine 102 Combustion chamber 103 Piston 104 Piston cavity 105 Cylinder 106 Cylinder head 107 Intake valve device 108 Intake port 109 Exhaust valve device 110 Spark plug 111 Intake passage

Claims (3)

  In a fuel injection valve for injecting fuel supplied from a fuel pipe to an internal combustion engine of an automobile, a zero ring for sealing between the fuel pipe and the fuel injection valve, and a backup ring for supporting the zero ring The backup ring has a notch that forms an angle with the axis of the fuel injection valve, has a protrusion on the inner diameter side that contacts the 0 ring, and partially contacts the outer diameter side of the fuel pipe Fuel injection valve characterized in that the surface is set The fuel injection valve according to claim 1, wherein
The fuel injection valve characterized in that the area of the opposite side surface is smaller than the 0-ring contact area of the backup ring. The fuel injection valve according to claim 1 or 2,
The fuel injection valve characterized in that the surface roughness of the opposite side surface is larger than the 0-ring contact surface roughness of the backup ring.