JP4221435B2 - Fuel injection device - Google Patents

Description

  The present invention relates to an improvement in a fuel injection device used for an internal combustion engine.

  In recent years, fuel pressure has been increased for the purpose of atomizing sprayed fuel and increasing the fuel flow rate. As a result, higher fuel sealing performance is required, but when the delivery pipe and the fuel injection device are misaligned due to dimensional variation of the delivery pipe and cylinder head and thermal expansion, the fuel sealing performance is reduced. There was a problem to do.

  Various studies have been made to eliminate the misalignment between the delivery pipe and the fuel injection device, and there is Patent Document 1 described later as an example of a conventional fuel injection device for an internal combustion engine. This describes a fuel injection device that absorbs axial misalignment between the delivery pipe and the fuel injection device by inserting intermediate pieces that are sealed by O-rings upstream and downstream between the delivery pipe and the fuel injection device, respectively. Yes.

  As an example 2 of the fuel injection device, as a method of absorbing the shaft misalignment, a connection between the delivery pipe and the fuel injection device in a fuel injection device that can be coupled to the delivery pipe by a screw connection portion as described in Patent Document 2 described later. There is a method in which a bellows member is provided in the portion.

  Further, as a third example of the fuel injection device, there is a method of absorbing a positional shift by attaching a bellows member to the delivery pipe side as in Patent Document 3 described later.

Furthermore, as Example 4 of the fuel injection device, there is a method of absorbing an axial deviation by elastically deforming the fuel injection device as in Patent Document 4 described later.
Special Table 2000-517032 Publication JP-A-55-10095 JP 2002-70687 A JP 2005-69090 A

  By the way, in the fuel injection device having the intermediate piece 25 as in Patent Document 1, since the shaft misalignment is absorbed by the fall of the intermediate piece as shown in FIG. . In addition, the number of parts increases and the structure becomes complicated. Furthermore, since the fuel injection device and the intermediate piece, and between the intermediate piece and the delivery pipe are sealed by O-rings, two seal rings are used. There was a problem of cost.

  As in Patent Document 2, the fuel injection device that is coupled to the delivery pipe by the screw connection portion has a problem that the workability when assembling the delivery pipe and the fuel injection device is poor.

  As in Patent Document 3, a delivery pipe serpentine member 26 is provided on the delivery pipe side to absorb the axis deviation. As shown in FIG. 4, the axis of the delivery pipe is inclined to cause the axis deviation. As in the case of Patent Document 1, there is a problem that an offset load is generated in the O-ring and the sealing performance is lowered.

  As shown in FIG. 5, as shown in FIG. 5, the delivery pipe and the shaft of the fuel injection device are also provided in the structure in which the fuel injection device is provided with the slit 27 and the fuel injection device is elastically deformed to absorb the shaft misalignment. Because of the tilt, there is a problem that an offset load is applied to the O-ring.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems in the prior art, which does not require an intermediate piece, can maintain a high fuel sealing performance even when an axial deviation occurs, and delivers a fuel injection device. An object of the present invention is to provide a fuel injection device that is excellent in attachment workability when attached to a pipe.

A fuel injection device according to the present invention includes a fuel receiving portion that is oil-tightly connected to a delivery pipe that supplies fuel via an O-ring, a valve body that opens and closes a fuel injection hole, and a core that includes a fuel flow path. A fuel injection device, wherein a fuel downstream end portion of the fuel receiving portion and a fuel upstream end portion of the core are connected by a bellows member, and the fuel receiving portion is connected to the outside of the bellows member of the fuel injection device. An intersecting movement restricting member that moves in an intersecting direction with respect to the shaft is provided, and one end of the intersecting movement restricting member is fixed to the core, and the other end is not fixed to the fuel receiving portion. It is characterized by this.

In the fuel injection device of the present invention, a bellows member is provided downstream of the O-ring and the fuel receiving portion, and a cross movement restricting member is provided at a position separated from the outer wall of the bellows member. One end of the cross movement restricting member is fixed to the core, and the other end is not fixed so that the fuel receiving portion can move in the cross direction with respect to the axis of the fuel injection device. Therefore, by providing the bellows member, the fuel receiving portion can move in the crossing direction with respect to the axis of the fuel injection device, and the cross movement restricting member is fixed to the core at one end. Although it moves and deforms the bellows member, the other end is free, so that the fuel receiving portion can move in the direction intersecting the axis of the fuel injection device. In addition, since the fuel receiving portion moves in the crossing direction, an uneven load on the O-ring is prevented and the above-described problems of the prior art are solved. Therefore, the high sealing performance of the fuel receiving portion is stably maintained.

In the following, the same parts in the drawings are given the same reference numerals.
Embodiment 1 FIG.
FIG. 1 is a cross-sectional view perpendicular to the operating axis of the fuel injection device according to Embodiment 1 of the present invention. In FIG. 1, the fuel injection device 1 includes a solenoid device 2, a yoke 3, a core 4, an armature 5 and a valve unit 6, and the solenoid device 2 has a coil assembly 7 and a coil 8. The valve unit 6 is coupled to one end of the valve holder 9 by means such as welding.

  The valve unit 6 is a valve having a hollow cylindrical valve body (valve main body) 10 whose outer portion is configured in a two-stage structure, and a nozzle having an injection hole 11 while being fixed to the tip of the central port in the valve body 10. The seat 12 is disposed between the valve seat 12 and the valve body 10, and a swirler (swivel body) 13 for giving a swirling flow to the injected fuel, and by contacting or leaving the valve seat 12 by the solenoid device 2, A needle valve (valve element) 14 that is a valve mechanism for opening and closing the nozzle hole 11 is provided.

  A metal sleeve 15 is disposed between the core 4 and the valve holder 9, and the sleeve 15 is fastened to the core 4 and the valve holder 9 by means such as welding. By being fastened in this way, the internal fuel is sealed so as not to leak. Fuel is supplied from the delivery pipe 17 to the fuel injection device. The fuel receiving portion 20 is composed of an O-ring 21 and a seal portion core 22 in order to oil-tightly connect the delivery pipe 17 and the fuel injection device 1, and its fuel downstream end portion, that is, the seal portion core 22. The downstream end of each is connected by means such as welding. The fuel downstream end of the bellows member 23 is connected to the fuel upstream end of the core 4 by means such as welding.

A pipe 24 as an example of the cross movement restricting member in the present invention is disposed on the entire bellows member 23 and an outer peripheral portion of one part of the core 4. The pipe 24 has a fuel downstream end fixed to the fuel upstream end of the core 4 by means such as welding, and the fuel upstream end is free from being joined to the seal core 22. Yes. By being free, there is an effect that the fuel receiving portion 20 described above can move in the direction intersecting the axis, but more preferably, as shown in FIG. In addition, it is preferable that the plane be perpendicular to the axis of the fuel injection device 1 and that the upper end surface of the pipe 24 be regulated by the lower end surface of the flat surface of the seal core 22 and be smoothly moved to the left and right.

  Next, the operation will be described. By passing a current through the coil 8, a magnetic flux is generated in the magnetic circuit composed of the armature 5, the core 4, and the yoke 3, and the armature 5 is attracted to the core 4 side. The needle valve 14 integrally formed with the amateur 5 is pressed against the valve seat 12 by a spring 19 fixed to the rod 18, but the needle 5 is sucked toward the core 4 side when the armature 5 is sucked. A gap is formed at the front end of the valve seat 12, and high-pressure fuel supplied from the delivery pipe 17 enters the injection hole 11 of the valve seat 12 from the valve body 10 and is injected from the outlet of the front end.

  When the fuel injection device 1 and the delivery pipe 17 are misaligned, the bellows member 23 installed downstream of the fuel receiving portion 20 is deformed, and the fuel receiving portion 20 moves to absorb the shaft misalignment. At that time, the fuel receiving portion 20 is pressed against and contacted with the upper end surface of the pipe 24 by the pressure of the fuel, so that the shaft of the fuel injection device and the shaft of the fuel receiving portion 20 move in parallel as shown in FIG. There is no inclination between the axis of the delivery pipe 17 and the axis of the fuel receiving portion 20. Therefore, an eccentric load is not generated in the O-ring 21 and high sealing performance is maintained.

  The present invention is expected to be used as a fuel injection device for various internal combustion engines.

1 is a cross-sectional view of a fuel injection device according to Embodiment 1 of the present invention. It is other sectional drawing of Embodiment 1 of this invention. It is sectional drawing of the conventional fuel-injection apparatus. It is sectional drawing of the other conventional fuel injection apparatus. It is sectional drawing of the other conventional fuel injection apparatus.

Explanation of symbols

1: fuel injection device, 2: solenoid device, 3: yoke, 4: core, 5: amateur,
6: valve unit, 7: coil assembly, 8: coil, 9: valve holder,
10: valve body, 11: nozzle, 12: valve seat, 13: swirler (swivel body),
14: Valve body, 15: Sleeve, 16: Cylinder head, 17: Delivery pipe,
18: Rod, 19: Spring, 20: Fuel receiving part, 21: O-ring, 22: Seal part core,
23: bellows member, 24: pipe.

Claims (3)

A fuel injection device comprising: a fuel receiving portion that is oil-tightly connected to a delivery pipe that supplies fuel via an O-ring; a valve body that opens and closes a fuel injection hole; and a core that includes a fuel flow path. the fuel upstream end of the fuel downstream end and the core of the fuel receiving portion is connected by a bellows member, the outside of the bellows member, the fuel receiving portion in the transverse direction to the axis of the fuel injector A cross movement restricting member for restricting movement is provided, and one end of the cross movement restricting member is fixed to the core, and the other end is not fixed to the fuel receiving portion. A fuel injection device. The intersecting movement restricting member is a fuel injection device according to claim 1, wherein the pipe. The fuel receiving portion and the cross movement restricting member are in contact with each other so as to be capable of mutual movement in a direction orthogonal to or close to the axis of the fuel injection device. Fuel injection device.

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