JP2575801Y2 - Unit injector - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION This invention relates to an improvement in a unit injector known as a fuel injector.

[0002]

2. Description of the Related Art In recent years, unit injectors are mainly combined with a solenoid valve (electromagnetic valve) for controlling fuel injection control. However, in the case where a solenoid valve is integrally formed beside a unit injector, It is difficult to mount the engine on a four-valve engine having a small space between valves. That is, in a four-valve engine, as shown in FIG. 2, the engine valve 62 is arranged so as to surround the unit injector body 1, so that if the solenoid valve 20 is provided integrally beside the unit injector body, the valve Since the space between them is small, the solenoid valve 20 interferes with the valve 62.

In order to solve this problem, conventionally,
As disclosed in Japanese Patent Application Laid-Open No. Sho 62-129562, it has been proposed to connect a unit injector body and a solenoid valve by an intermediate piece having a fuel passage, and to draw out and arrange the solenoid valve outside the engine valve. .

[0004]

However, since the solenoid valve is fixed to the engine head separately from the unit injector main body, if the unit injector main body 1 and the solenoid valve 20 are accompanied by a positional shift, the position is shifted. The burden is placed on the intermediate piece by the amount, and the sealing performance deteriorates at the joint with the intermediate piece,
In this case, the intermediate piece itself may be damaged.

Therefore, in the present invention, in a configuration in which the unit injector body and the solenoid valve are connected via an intermediate pipe, even if the unit injector and the solenoid valve are displaced when fixed, the intermediate pipe is damaged. It is an object of the present invention to provide a unit injector which can maintain a good sealing property without using the same.

[0006]

In order to solve the problems] Thus, Yu of this invention
Knit injector unit injector body in the unit injector is connected to the solenoid valve via an intermediate pipe having a fuel passage, lies in providing the easily variable portion deforms before Symbol in <br/> between pipes.

[0007]

[Effect] Therefore, even if the displacement occurs when the solenoid valve is fixed or the unit injector body is fixed,
Since the intermediate pipe is easily deformed by the variable portion, the variable portion can be deformed to absorb the positional shift, and thus the above-mentioned object can be achieved.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

1 and 2, the unit injector has, for example, a unit injector main body 1 for injecting fuel into each cylinder of a diesel engine. The unit injector main body 1 is formed at a base of a plunger barrel 2. A plunger 4 is slidably inserted into the cylinder 3, and a compression chamber 5 is formed in a portion surrounded by the plunger barrel 2 and the plunger 4. The plunger 4
Is always urged in a direction away from the plunger barrel 2 (upward in the figure) by a spring 7 interposed between the tappet 6 and the plunger barrel 2 integrally formed at the base thereof. The tappet 6 is in contact with a cam formed on a drive shaft of an engine (not shown). When the drive shaft rotates, the plunger 4 reciprocates in cooperation with the spring 7.

A holder 8 is attached to the tip of the plunger barrel 2 with a holder nut 9, and a nozzle 11 is connected to the holder 8 via a spacer 10 with a retaining nut 12. A spring storage chamber 13 is formed in the holder portion 8, and the nozzle spring 14 stored in the spring storage chamber 13
The needle valve of a nozzle (not shown) is pressed downward in the figure. The nozzle 11 has a well-known structure itself. The nozzle 11 has a communication hole 16 formed in the plunger barrel 2 from the compression chamber 5 at the tip of the plunger, and a communication hole 17 formed in the plunger barrel 2. When the fuel is supplied to the nozzle 11 through the communication hole 18 formed in the nozzle, the needle valve is opened, and fuel is injected from the injection hole formed at the tip of the nozzle.

The solenoid valve 20 is provided with a sliding hole 2 of a valve housing 21 provided independently of the plunger barrel 2.
2, a valve body 23 is slidably inserted. In this solenoid valve 20, a solenoid housing barrel 33 is connected to a valve housing 2 by a holder nut 34 via a spacer 32.
An armature 31, which is screwed to the tip of the valve body 23, is attached to the valve housing 21 and the spacer 3.
2 is housed in an armature chamber 35 formed between
It faces the solenoid 37 housed in the solenoid housing barrel 33 via the spacer 32. This solenoid 37 is formed by housing a coil 39 in a stator 38,
The end face of the stator 38 is aligned with the end face of the spacer 32.

An annular recess 40 is formed in a portion of the valve housing 21 near the armature so as to face the side surface of the valve body 23. The end of the annular recess 40 on the armature side is tapered. Valve seat 4 that part 41 contacts
2, the annular chamber 44 surrounded by the annular recess 40 and the valve body 23 in a state where the tapered portion 41 and the valve seat 42 are separated from each other.
The communication between the annular chamber 44 and the armature chamber 35 is interrupted in a state where the armature chamber 35 communicates with the first armature 35 and the tapered portion 41 contacts the valve seat 42.

The valve housing 21 has a tapered portion 41 formed in a spring storage chamber 45 formed on the side surface of the valve body 22.
A return spring 46 for urging the valve in a direction in which it is always separated from the valve seat 42 is housed. Therefore, only when the solenoid 37 is energized, the armature 31 is attracted to the stator 38 against the return spring 46, and the tapered portion 41 is seated on the valve seat 42. Also, the spring storage chamber 45 and the armature chamber 35
Are communicated by a communication passage 47.

A sliding hole 22 formed in the valve housing 21
Is closed airtightly from outside by an adjusting plug 48, and the adjusting plug 48 forms a stopper for the valve element 23. By adjusting the amount of screwing of the adjusting plug 48, the solenoid valve 2 is closed.
The maximum opening amount of 0 can be adjusted.

Further, a fuel inlet 49a for supplying fuel and a fuel outlet 49b for discharging fuel are formed in the armature chamber 35, and a check valve is provided in the fuel outlet 49b. The excess fuel is returned to the fuel tank.

The unit injector body 1 and the solenoid valve 20 are connected by an intermediate pipe 50 also shown in FIG. More specifically, the intermediate pipe 50
Is connected to the unit injector main body 1 by screwing a male screw part 51 formed therein to a female screw part 52 screwed on the side of the plunger barrel 2,
The other end of the intermediate pipe 50 is connected to the solenoid valve 20 by screwing a retaining nut 53 provided on the intermediate pipe 50 to a female screw portion 54 screwed on a side portion of the valve housing 21.

In the middle of the intermediate pipe 50, a deformed portion 65 is provided.
In this embodiment, a deformed portion 65 is formed by a constricted portion 55 provided in an annular shape on the surface of the pipe, and the constricted portion 55 allows the portion to be deformed more easily than both ends of the intermediate pipe 50. And

A fuel supply passage for supplying fuel from the annular chamber 44 to the compression chamber 5 has one end connected to the fuel passage 56 formed in the intermediate pipe 50 and the annular chamber 44 of the valve housing 21 and the other end connected to the middle. A communication passage 57 connected to one end of a fuel passage 56 of the pipe 50, one end connected to the other end of the fuel passage 56 of the intermediate pipe 50, and the other end connected to the plunger barrel 2.
And a communication path 58 that communicates with the communication path 16 formed in the communication path.

Reference numeral 60 denotes a fuel leak passage, the tip of which is connected to an annular groove 61 provided so as to face the side surface of the plunger 4 so as to supply lubricating oil around the plunger. The energization of the solenoid 37 is controlled by a control unit (not shown). The control unit calculates the energization start and end timings based on various signals, and energizes the solenoid 37 for a required time during the compression stroke. Then, the closing period of the solenoid valve 20 is controlled.

During the suction stroke in which the plunger 4 moves upward, the solenoid 35 is not energized, so that the armature 31 is separated from the stator 38 by the spring force of the return spring 46, and at the same time, the tapered portion 41 is separated from the valve seat 42 The low-pressure fuel introduced from the fuel inlet 49 is supplied to the compression chamber 5 via the annular chamber 44 and the fuel supply passage. In the compression stroke, the solenoid 37
Since the energization of the armature 31 is started, the armature 31 is attracted to the stator 38, and the tapered portion 41 is seated on the valve seat 42. As a result, the communication between the low pressure side and the high pressure side is cut off, and the fuel in the compression chamber 5 is compressed and injected from the nozzle 11.

In the latter half of the compression stroke, the solenoid 37
Since there is no current supply to the valve seat 41 again, the tapered portion 41
2, the high-pressure fuel on the high-pressure side is returned to the armature chamber 35 via the fuel supply passage and the annular chamber 44, and the pressure on the high-pressure side is suddenly reduced to terminate the injection.

In order to mount the above-described unit injector on a four-valve engine, as shown in FIG. , And the solenoid valve 20 is fixed to an engine head (not shown) by a predetermined fixing means. On this occasion,
The mounting position of the unit injector main body 1 and the mounting position of the solenoid valve 20 are determined with a predetermined accuracy. Conversely, the mounting positions are shifted within this accuracy range. Due to this displacement, a load is applied to the intermediate pipe 50. However, the deformed portion 55 provided on the intermediate pipe 50 is partially constricted so as to be easily deformed. It is absorbed by the deformation of the deformable portion 55, thereby preventing damage to the intermediate pipe itself and preventing the sealing state of the connection portion between the intermediate pipe 50 and the unit injector main body 1 or the connection portion between the intermediate pipe 50 and the solenoid valve 20 from being reduced.

FIGS. 4 and 5 show another embodiment of the present invention. In the embodiment of FIG. 4, a plurality of constrictions 55 are formed around the pipe as a deformed portion 65 of the intermediate pipe 50. Further, a structure may be adopted in which the intermediate pipe 50 is subjected to heat treatment instead of the constriction 55 to easily deform a predetermined intermediate portion (indicated by a broken line area). For example, it is conceivable that the joints at both ends of the intermediate pipe 50 are strengthened by quenching, and a predetermined intermediate portion is structured to allow deformation by tempering. In these other embodiments as well, the displacement that occurs when the unit injector body 1 and the solenoid valve 20 are fixed can be absorbed in the same manner as in the previous embodiment.

[0024]

[Effect of the invention] As described above, according to the invention,
Since the unit injector and the solenoid valve are connected with an intermediate pipe having a deformable variable part,
Even if the unit injector body and the solenoid valve are each displaced and fixed so that a load is applied to the intermediate pipe, the displacement is absorbed by the deformation of the variable part of the intermediate pipe, and the intermediate pipe is not damaged and A good sealing state can be maintained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a unit injector according to the present invention.

FIG. 2 is a schematic diagram showing a state where the unit injector according to the present invention is assembled to a four-valve engine.

FIG. 3 is a sectional view showing an embodiment of an intermediate pipe of the unit injector according to the present invention.

FIG. 4 and

FIG. 5 is a sectional view showing another embodiment of the intermediate pipe of the unit injector according to the present invention.

[Explanation of symbols]

 1 Unit Injector Body 20 Solenoid Valve 50 Intermediate Pipe 56 Fuel Passage 65 Variable Section

Claims (1)

(57) [Scope of request for utility model registration] 1. A unit unit injector, characterized in that in the unit injector which is connected to the solenoid valve through the intermediate pipe is provided with a pre-Symbol deformed intermediate pipe easily variable region having an injector body fuel passage.