JP2003120470A - Fluid passage connection structure, and fuel injector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily work and assemble passage forming members to connect separate fluid passages in such a manner to abut on each other. SOLUTION: A communication pipe 33 is held by an expanded recessed part 31 to fold an opening side end part of a first fuel feed passage 18 of a holder body 11 and an expanded recessed part 32 to form an opening side end part of a second fuel feed passage 22 of an intermediate member 14. The communication pipe 33 is elastically deformed by the pressure applied from the high- pressure fuel so that the entire communication pipe is expanded in the radial direction, and the entire outer circumferential surface 33b thereof is pressed against inner circumferential surfaces 31b and 32b of the expanded recessed parts 31 and 32. The entire circumferential surface is elastically deformed in an expanding manner in the axial direction, and each circumferential end face 33a is pressed against the entire circumference of bottom surfaces 31a and 32a of the expanded recessed parts 31 and 32. In this condition, the communication pipe 33 communicates the fuel feed passages 18 and 22 with each other in the sealed manner.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid passage connecting structure, and more particularly to a fluid passage connecting structure such as a fuel passage separated into two passage forming parts of a fuel injector for a diesel engine, And a fuel injector provided with the same connection structure.

[0002]

2. Description of the Related Art Conventionally, for example, in an injector used in a common rail fuel injection system for a diesel engine, as shown in FIGS. 12 (a) and 12 (b), a nozzle body 71 is attached to a holder body 70 together with an intermediate member 72. Some have a structure in which they are clamped and fixed by a retaining nut 73.

The injector is provided with a fuel supply passage 75 for supplying high-pressure fuel from a fuel supply joint (not shown) provided on the holder body 70 to an oil sump 74 provided on the nozzle body 71. There is.
The fuel supply passage 75 is formed by fuel supply passages 75 a, 75 b, and 75 c provided in the holder body 70, the intermediate member 72, and the nozzle body 71, respectively. That is, the fuel supply passage 75 is separated between the holder body 70 and the intermediate member 72, which are in contact with each other, and between the intermediate member 72 and the nozzle body 71. In this way, the holder body 70, the intermediate member 72, and the nozzle body 71 are separated because the fuel supply passage 75, the piston chamber 76, the needle chamber 77, the oil sump 74,
This is for processing the injection holes 78 and the like.

On the other hand, the pressure of the fuel supplied from the supply pump to each injector via the common rail reaches 130 MPa, for example. Therefore, with respect to the fuel supply passage 75 provided separately in three members, between the holder body 70 and the intermediate member 72 and the intermediate member 7
It is necessary to make a strong seal between the nozzle 2 and the nozzle body 71.

However, if a gasket, which is an elastic sealing member, is used to seal the fuel supply passage between the abutting members, the lift amount of the needle 79,
The variation of the set load of the spring 80 becomes large.
This is because the lift amount and the set load are determined by the positional relationship between the holder body 70 and the nozzle body 71 in the axial direction, while the gasket disperses the positional relationship between the holder body 70 and the nozzle body 71. is there. Therefore, when the gasket is used to seal the fuel supply passage 75 between the two members, variations in fuel injection timing and fuel injection amount increase.

Further, the fuel supply passage 75 can be connected between both members by using the taper fitting by the joints having the taper surfaces, which is used for connecting the fuel pipe connecting the supply pump and the common rail. Conceivable. However, even in this connection structure, the holder body 70 and the intermediate member 72 are formed in order to make the joints taper-fit.
Cannot be brought into close contact with each other, and the positional relationship in the axial direction varies. Therefore, the variations in the needle lift amount and the spring set load increase, and the variations in the fuel injection amount and the fuel injection timing also increase.

Therefore, at present, the contact end surfaces 70a, 7a of the holder body 70 and the intermediate member 72 which contact each other are present.
2a, and similarly, the intermediate member 72 and the nozzle body 7
The fuel supply passage 75 to be connected is hermetically sealed by tightening the retaining nut 73 so that the respective abutting end surfaces 72b and 71a with 1 are brought into close contact with each other. In order to make such a connection, the abutting end surfaces 70a, 72a, 72 of the holder body 70, the intermediate member 72 and the nozzle body 71 are formed.
b and 71a are precision ground, and both contact end surfaces 70a and 72a
It is assembled so that dust does not enter between a, 72b, and 71a.

[0008]

However, in the connection structure of the fuel supply passage 75 as described above, the abutting end surfaces 70a, 71a, 72a, 72b of the holder body 70, the intermediate member 72 and the nozzle body 71 are precisely ground. In order to achieve this, a precision surface grinding machine is required, and there is a problem that the processing time becomes longer than that of normal grinding. Further, at the time of assembly, dust may not enter even between the abutting end surfaces 70a and 72a of the holder body 70 and the intermediate member 72 and between the abutting end surfaces 72b and 71a of the intermediate member 72 and the nozzle body 71. Therefore, there is a problem that a clean environment such as a clean factory is required.

Further, as another problem, in a connection structure using a gasket or a connection structure in which joints are taper-fitted with each other, the size required in the radial direction becomes large. For this reason, it is necessary to reduce the wall thickness of the nozzle body 71 and the intermediate member 72 whose diameters are limited, and there is also a problem that the strength of each member becomes weak.

The present invention has been made in order to solve the above problems, and an object thereof is to process both passage forming members which connect fluid passages, which are separately provided, in a state of abutting each other. Another object of the present invention is to provide a fluid passage connecting structure that can be assembled more easily, and can reduce the size required in the radial direction, and a fuel injector provided with the connecting structure.

[0011]

In order to solve the above-mentioned problems, the invention according to claim 1 is characterized in that two passage forming members each having a fluid passage are opened in each passage forming member. A structure for connecting fluid passages in which the abutting end surfaces of the fluid passages are held in contact with each other and the fluid passages are connected to each other between the passage formation members. A diameter-increasing concave portion that forms an end portion is provided, and the diameter-increasing concave portions that are communicated in a state where the abutting end surfaces are in contact with each other hold a communication pipe for connecting the two fluid passages, The communication pipe connects the two fluid passages to each other and seals the two fluid passages communicated with each other between the contact end surfaces while the outer surface of the communication pipe is in pressure contact with the inner surface of each of the enlarged diameter recesses. Characterized by .

According to the first aspect of the present invention, the abutting end faces of the passage forming members are abutted with each other, and the fluid passages are abutted between the abutting end faces with the positional relationship between the abutting end faces being fixed. It is connected in a sealed state. Therefore, since both contact end surfaces are surely contacted with each other, the positional relationship between them does not vary, and since it is not necessary to bring the contact end surfaces of both passage forming members into close contact with each other, precision grinding or assembly in a clean environment is required. No work required.

According to a second aspect of the present invention, in the first aspect of the present invention, the communicating pipe is elastically deformed by the pressure applied from the fluid supplied to the fluid passages, and the outer surface of the communicating pipe is expanded by the diameters. It is characterized in that the inner surfaces of the recesses are pressed against each other.

According to the invention of claim 2, claim 1
In addition to the operation of the invention described in (1), since the communication pipe is pressed against the inner surface of each expanded diameter recess by the pressure applied from the fluid supplied to each fluid passage, there is dimensional variation in each expanded recess and the communication pipe. Both fluid passages are more reliably sealed.

According to a third aspect of the present invention, in the invention according to the second aspect, the communicating pipe is elastically deformed so as to be expanded in diameter and elastically deformed so as to be elongated in the axial direction. Each of the end portions is pressed against the bottom surface of each of the enlarged diameter concave portions.

According to the invention of claim 3, claim 2
In addition to the effect of the invention described in (1), since the respective end portions in the axial direction of the communication pipe are pressed against the bottom surfaces of the respective expanded diameter recesses,
The fluid passage is more reliably sealed than in the case where the peripheral surface of the communication pipe is pressed.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the communicating pipe is elastically deformed by being sandwiched in the axial direction by the both passage forming members, and its outer surface is expanded by each diameter. It is characterized in that the inner surfaces of the recesses are pressed against each other.

According to the invention of claim 4, claim 1
In addition to the effect of the invention described in (1), since the communication pipe is preliminarily pressed against the inner surface of each of the expanded diameter recesses by both passage forming members,
Even if the pressure of the fluid in the fluid passage decreases, both fluid passages are more reliably sealed.

According to a fifth aspect of the invention, in the invention according to the fourth aspect, the communicating pipe presses each end portion in the axial direction into pressure contact with the bottom surface of each of the enlarged diameter recesses. Characterize.

According to the invention of claim 5, claim 4
In addition to the effect of the invention described in (1), since the respective end portions in the axial direction of the communication pipe are pressed against the bottom surfaces of the respective expanded diameter recesses,
The fluid passage is more reliably sealed than in the case where the peripheral surface of the communication pipe is pressed.

According to a sixth aspect of the present invention, in the invention according to the fourth aspect, each end portion of the communicating tube in the axial direction is respectively formed with respect to an inner corner portion of a bottom surface of each of the enlarged diameter recesses. It is characterized in that the both ends are brought into pressure contact with each other and elastically deformed so as to be expanded by a pressure applied from the fluid supplied to each of the fluid passages, and the both ends are brought into pressure contact with the inner corner portions.

According to the invention of claim 6, claim 4
In addition to the effect of the invention described in (1), both fluid passages are more reliably sealed even if the communication pipe and each diameter-increasing recess have dimensional variations, or even if the fluid pressure in the fluid passage decreases.

According to a seventh aspect of the invention, in the invention according to any one of the first to sixth aspects, the both passage forming members are a holder body of a fuel injector for an engine, and the holder body. Is an intermediate member or a nozzle body that is fastened and fixed by a retaining nut to the communication pipe, and the communication pipe includes the diameter-increasing concave portion that forms an opening-side end portion of a fuel supply passage provided in the holder body, and the intermediate member or It is characterized in that it is held by the diameter-increasing concave portion that forms the opening-side end of the fuel supply passage provided in the nozzle body.

According to the invention of claim 7, claim 1
In addition to the action of the invention according to any one of claims 6 to 6, in a fuel injector for an engine, a holder body and an intermediate member or a nozzle body tightened and fixed to the holder body by a retaining nut are provided. A connection structure for separate fuel supply passages.
~ It has the effect of the invention described in any one of claims 6.

The invention described in claim 8 is characterized by including the fluid passage connecting structure according to claim 7.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment in which the present invention is embodied in a fuel passage connecting structure in a fuel injector for a common rail type injection system of a diesel engine will be described with reference to FIGS. To do.

As shown in FIG. 2, the fuel injector 1
Reference numeral 0 denotes a known structure, which includes the holder body 11 and the solenoid valve 1.
2, an upper retaining nut 13, an intermediate member 14, a nozzle body 15, a lower retaining nut 16 and the like. In this embodiment, each of the holder body 11 and the intermediate member 14 is a passage forming member.

An electromagnetic valve 12 is fixed to an upper portion of the holder body 11 by an upper retaining nut 13. The holder body 11 is provided with a fuel supply side joint 17, a first fuel supply passage 18, a fuel return passage 19, a fuel return side joint 20, and the like. A bar filter 21 is mounted in the fuel supply side joint 17.

The intermediate member 14 is provided with a second fuel supply passage 22 connected to the first fuel supply passage 18. In this embodiment, the first fuel supply passage 18 and the second fuel supply passage 22 are fluid passages.

A piston chamber 23 is formed by the holder body 11 and the intermediate member 14. Piston chamber 23
The command piston 24, the spring 25, and the like are housed in the.

As shown in FIG. 3, the nozzle body 15 is
A third fuel supply passage 26, which is connected to the second fuel supply passage 22, a needle chamber 27, an oil sump 28, an injection hole 29, and the like are provided therein. A needle 30 is accommodated in the needle chamber 27.

The intermediate member 14 and the nozzle body 15 are the lower retaining nut 1 screwed to the holder body 11.
It is integrated with the holder body 11 by being sandwiched between 6 and the holder body 11. First fuel supply passage 18
The second fuel supply passage 22 includes the lower end surface 11 a of the holder body 11 and the upper end surface 14 of the intermediate member 14, which are in contact with each other.
It is connected to a. Similarly, the second fuel supply passage 22 and the third fuel supply passage 26 are connected between the lower end surface 14b of the intermediate member 14 and the upper end surface 15a of the nozzle body 15 that are in contact with each other. In this embodiment, the lower end surface 11a and the upper end surface 14a are contact end surfaces, respectively.

When the injector 10 is not energized, the solenoid valve 12 is closed so that the high pressure fuel supplied from the fuel supply side joint 17 to the upper side (command chamber) of the piston chamber 23 does not escape. The command piston 24 is moved downward by the pressure. Then, the needle 30 is moved downward together with the spring 25, and the high-pressure fuel supplied to the oil sump 28 and the needle chamber 27 via the first to third fuel supply passages 18, 22, and 26 is not injected from the injection hole 29. To do so. On the other hand, when energized, the solenoid valve 12
Releases the high-pressure fuel supplied to the command chamber from the fuel supply side joint 17 and removes the pressure that is pressing the command piston 24. As a result, the needle 30 moves upward,
The high-pressure fuel supplied to the oil sump 28 and the needle chamber 27 via the first to third fuel supply passages 18, 22, and 26 is injected from the injection hole 29.

The first fuel supply passage 18 of the holder body 11
And the second fuel supply passage 22 of the intermediate member 14 are connected by the connection structure of the present embodiment. The second fuel supply passage 22 of the intermediate member 14 and the third fuel supply passage 26 of the nozzle body 15 are connected by a conventional connection structure.

Next, the connection structure of the first fuel supply passage 18 and the second fuel supply passage 22 between the holder body 11 and the intermediate member 14 will be described in detail. Figure 1 (a),
As shown in (b), the connection structure according to the present embodiment has a diameter-increasing recess 31 provided in the holder body 11 and an intermediate member 14.
And a communicating pipe 33 held by both the diameter-increasing recesses 31 and 32.

As shown in FIGS. 4 (a) and 4 (b), the enlarged-diameter recess 31 of the holder body 11 has a columnar shape that forms the opening-side end of the first fuel supply passage 18 that opens to the lower end surface 11a thereof. And has an annular bottom surface 31a (inner surface).

Similarly, the enlarged diameter concave portion 32 of the intermediate member 14 is
As shown in FIG. 1A, the second fuel supply passage 22 has an annular bottom surface 32a, which is provided in a columnar shape and forms an opening-side end portion of the second fuel supply passage 22 opening at the upper end surface 14a.

As shown in FIGS. 5 (a) and 5 (b), the communication pipe 33 is formed in a substantially cylindrical shape, and is separated in the axial direction by two.
It has two enlarged diameter portions 34 having the same outer diameter, and also has a pair of peripheral end surfaces 33a (outer surfaces) as outer surfaces. That is, the communication pipe 33 is formed in a substantially bellows shape in a side view. The communication pipe 33 of this embodiment is integrally formed of stainless steel.

As shown in FIGS. 6 (a) and 6 (b), in the communication pipe 33, the lower end surface 11a of the holder body 11 and the upper end surface 14a of the intermediate member 14 are brought into contact with each other when the injector 10 is assembled. Diametrical expansion recesses 3 that communicate with each other in the closed state
1 and the enlarged diameter recess 32. At this time, in the communication pipe 33, each peripheral end surface 33a is
The bottom surfaces 31a and 32a of 32 are abutted on the entire circumference and supported in the axial direction. Further, in the communication pipe 33, the expanded diameter portions 34 are lightly fitted into the expanded diameter recesses 31 and 32, respectively, and are supported in the radial direction with respect to the axial direction.

As described above, the communication pipe 33 held by both the enlarged diameter recesses 31 and 32 is subjected to the pressure applied from the high-pressure fuel supplied to the first fuel supply passage 18 as shown in FIG.
As shown in (b), the entire outer peripheral surface 33b is elastically deformed so as to increase the diameter, and the entire outer peripheral surface 33b is pressed against the inner peripheral surfaces 31b and 32b of the respective diameter expanded recesses 31 and 32. And this elastic deformation causes the whole to expand in the axial direction,
Each of the peripheral end faces 33a is a bottom face 31 of each of the expanded diameter recesses 31, 32.
It is pressed against a and 32a over the entire circumference.

In this state, the communication pipe 33 connects the first fuel supply passage 18 and the second fuel supply passage 22 inside thereof. Then, the two fuel supply passages 18, which are communicated with each other,
22 is a peripheral end surface 33a that is in pressure contact with the bottom surfaces 31a and 32a of the expanded diameter recessed portions 31 and 32, and the expanded diameter recessed portions 31a and 32a.
The inner peripheral surfaces 31b and 32b of 32 and the outer peripheral surface 33b that are in pressure contact with each other seal between the contacted end surfaces 11a and 14a.

According to this embodiment described in detail above, the following respective effects can be obtained. (1) Lower end surface 11a of holder body 11 and intermediate member 1
4, the fuel supply passages 18, 22 are connected to each other in a sealed state between the both end surfaces 11a, 14a with the upper end surface 14a of the No. 4 abutting on each other and the positional relationship therebetween being fixed.

Therefore, since the both end surfaces 11a and 14a are reliably brought into contact with each other, the positional relationship between the holder body 11 and the intermediate member 14 does not vary, and it is not necessary to bring the end surfaces 11a and 14a into close contact with each other, so that precision grinding is possible. Is unnecessary.

As a result, the fuel supply passages 18 and 22 that are separately provided in the holder body 11 and the intermediate member 14 that are held in contact with each other do not affect the positional relationship between the two members 11 and 14. It can be connected in a sealed state. Moreover, the processing and assembly of the members 11 and 14 can be performed more easily without using a precision grinder and without requiring a clean factory.

(2) Further, the enlarged diameter recessed portion 31 and the enlarged diameter recessed portion 3
2 and the communication pipe 33 held by the two fuel supply passages 1
A connection structure is provided in which 8, 22 are sealed between both end surfaces 11a, 14a. Therefore, unlike a connection structure in which a gasket or an O-ring is interposed between both end surfaces 11a and 14a for sealing, the size required in the radial direction of both fuel supply passages 18 and 22 can be smaller. Therefore, in the injector 10 whose radial dimension is limited, the structural strength of the holder body 11 and the intermediate member 14 is not significantly reduced.

(3) The communication pipe 33 is connected to the fuel supply passage 1
8 and 22 is elastically deformed by the pressure applied from the high-pressure fuel supplied to both of the peripheral end faces 33a and the outer peripheral face 33b,
The bottom surface 31a, 32a and the inner peripheral surface 31b, 32b of each of the expanded diameter recesses 31, 32 are brought into close contact with each other. Therefore, each diameter-increasing concave portion 3
The fuel supply passages 18, 22 are more reliably sealed between the both end surfaces 11a, 14a even if there is dimensional variation in the 1, 32 or the communication pipe 33.

(4) The communicating pipe 33 elastically deforms so as to expand in the radial direction and expands in the axial direction, and both circumferential end faces 33a in the axial direction are formed on the bottom surfaces 31a of the expanded diameter recesses 31, 32. It is brought into pressure contact with 32a. Therefore, each diameter-increasing concave portion 3
Both fuel supply passages 18 and 22 are more reliably sealed even if there is a dimensional variation in 1, 32 or the communication pipe 33.

(5) Conventionally, since the rotational positional relationship between the holder body 11 and the intermediate member 14 can be fixed by the communication pipe 33, it is not necessary to provide a knock pin for positioning as in the conventional case.

(Second Embodiment) Next, a second embodiment in which the present invention is embodied in a connection structure of the fuel supply passages 18, 22 of the fuel injector 10 which is the same as the first embodiment will be described with reference to FIGS. Follow the instructions below. The present embodiment differs from the first embodiment only in that the diameter-increasing recesses 31 and 32 and the communication pipe 33 of the first embodiment are changed to the diameter-increasing recesses 41 and 42 and the communication pipe 43. Therefore, regarding the same configuration as that of the first embodiment, the same reference numerals are used and the description thereof is omitted, and only the enlarged diameter recesses 41 and 42 and the communication pipe 43 will be described in detail.

As shown in FIGS. 7 (a) and 7 (b), the connection structure of this embodiment has a holder body 11 and an intermediate member 14.
The enlarged diameter recesses 41 and 42 provided in the
The communication pipe 43 is held by 42.

As shown in FIGS. 8 (a) and 8 (b), the enlarged diameter recess 41 of the holder body 11 forms a substantially circular shape which forms the opening side end of the first fuel supply passage 18 which opens to the lower end surface 11a thereof. It is provided in a columnar shape and has a bottom surface 41a (inner surface) in the shape of an annular taper. Similarly, the enlarged diameter recess 42 of the intermediate member 14 is
As shown in FIG. 7 (a), the second fuel supply passage 22 is opened in the upper end surface 14a thereof and is provided in a substantially columnar shape that forms the end portion on the opening side of the second fuel supply passage 22. is doing.

As shown in FIGS. 9 (a) and 9 (b), the communication tube 43 is formed in a hollow spindle shape with both ends open, and is formed in a substantially Japanese drum shape in a side view. The communication pipe 43 of this embodiment is integrally formed of stainless steel.

As shown in FIGS. 7A and 7B, the communication pipe 43 is communicated with the lower end surface 11a of the holder body 11 and the upper end surface 14a of the intermediate member 14 in contact with each other. It is held by the enlarged diameter recesses 41 and 42. At this time, the communication pipe 43 is axially aligned with the outer peripheral surface 43a (outer surface) of each end portion in the axial direction contacting the inner corner portions 41b and 42b of the bottom surfaces 41a and 42a over the entire circumference. It is pinched. And the communication pipe 43 is
By sandwiching both ends in this way, they are supported in the axial direction and the radial direction. Further, the communication pipe 43 is elastically deformed so that the central portion thereof is expanded in diameter by sandwiching both ends thereof in the axial direction, and the outer peripheral surface 43a of the central portion is formed inside the expanded diameter recessed portions 41, 42. The peripheral surfaces 41c, 42c are pressed against the opening-side peripheral edges in a strip shape over the entire circumference.

As described above, the communication pipe 43 held by the both diameter-increasing recesses 41, 42 is elastically deformed so that the entire diameter is expanded by the pressure applied from the high-pressure fuel supplied to the first fuel supply passage 18, The outer peripheral surface 43a of the end is the bottom surface 41
The inner corner portions 41b and 42b of the a and 42a are pressed against each other more strongly over the entire circumference. At the same time, the outer peripheral surface 43a of the central portion is more strongly pressed against the opening-side peripheral edges of the inner peripheral surfaces 41c and 42c of the expanded diameter recesses 41 and 42 over the entire circumference.

In this state, the communication pipe 43 internally connects the first fuel supply passage 18 and the second fuel supply passage 22. Then, the two fuel supply passages 18, 22 which are communicated with each other
By means of the outer peripheral surfaces 43a of both ends pressed against the inner corners 41b, 42b of the bottom surfaces 41a, 42a.
Seal between a and 14a.

According to this embodiment described in detail above, the following effects can be obtained in addition to the effects described in (1) to (3) of the first embodiment. (5) The communication pipe 43 is, as described in (2) above,
In addition to being elastically deformed by the pressure applied from the high-pressure fuel, the fuel supply passages 18 and 22 are sealed by being sandwiched in advance by the holder body 11 and the intermediate member 14. Therefore, the fuel supply passages 18 and 22 can be more reliably sealed even if the diameter expansion recesses 41 and 42 and the communication pipe 43 have dimensional variations and the pressure of the supplied fuel is reduced. it can.

(Third Embodiment) Next, the present invention will be described with reference to the same fuel supply passage 1 of the injector 10 as in the first embodiment.
FIG. 10 shows a third embodiment embodied in the connection structure of 8 and 22.
And FIG. 11 will be described. The present embodiment differs from the first embodiment only in that the communication pipe 33 of the first embodiment is changed to the communication pipe 51. Therefore, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted. Only the communication pipe 51 will be described in detail.

As shown in FIGS. 10A and 10B, in the connection structure of this embodiment, the diameter-increasing recess 31 provided in the holder body 11 and the diameter-increasing recess 32 provided in the intermediate member 14 are provided.
And the communication pipe 5 held by both the expanded diameter recesses 31 and 32.
1 and 1.

As shown in FIGS. 11 (a) and 11 (b), the communication pipe 51 is formed in a hollow Japanese drum shape with both ends in the axial direction open. Further, the outer peripheral corner portion 52a of each circumferential end surface 52 of the communicating pipe 51 in the axial direction is positioned outward of the inner peripheral corner portion 52b in the axial direction. The communication pipe 51 of this embodiment is integrally formed of stainless steel.

As shown in FIGS. 10 (a) and 10 (b), the communication pipe 51 is communicated with the lower end surface 11a of the holder body 11 and the upper end surface 14a of the intermediate member 14 in contact with each other. It is held by the enlarged diameter recesses 31 and 32.
At this time, in the communication pipe 51, the outer corner portions 52a (outer surfaces) of the respective peripheral end surfaces 52 have the bottom surfaces 31 of the respective radially enlarged recesses 31, 32.
A and 32a (inner surface) are axially sandwiched in a state of being in contact with each other over the entire circumference. And the communication pipe 51
Is axially supported by being sandwiched in the axial direction via both outer corner portions 52a. Furthermore, the communication pipe 51
The two outer corner portions 52a are elastically deformed so that the central portion thereof is expanded by being sandwiched in the axial direction, and the outer peripheral surface 51a (outer surface) of the central portion is located inside The peripheral surfaces 31b and 32b (inner surfaces) are pressed in a strip shape over the entire circumference with respect to the peripheral edges on the opening side.

In this way, the communication pipe 51 held by the both diameter-increasing concave portions 31 and 32 makes the both fuel supply passages 18 and 22 communicate with each other inside thereof. Then, the two fuel supply passages 18 and 22 communicated with each other are connected to the outer corner portions 52a and the inner peripheral surfaces 31b and 3 which are in pressure contact with the bottom surfaces 31a and 32a, respectively.
The outer peripheral surface 51 of the central portion pressed against the peripheral edge of the opening 2b
With a, the both end faces 11a and 14a are doubly sealed.

According to this embodiment described in detail above, in addition to the effects described in (1) and (2) of the first embodiment, the following effects can be obtained. (6) The communication pipe 51 includes the holder body 11 and the intermediate member 1.
It is elastically deformed so as to be expanded in diameter by being sandwiched by 4 and 4 in the axial direction. Then, the outer corner portions 52a of the both circumferential end surfaces 52 in the axial direction are formed on the bottom surface 31a of each of the expanded diameter recesses 31, 32,
It is brought into pressure contact with 32a. In addition, the outer peripheral surface 51a of the central portion,
The inner peripheral surfaces 31b, 32b of the respective diameter-expanded recesses 31, 32 are brought into pressure contact with the peripheral edges on the opening side. Therefore, the fuel supply passages 18 and 22 can be more reliably sealed even if the diameter-expanded recesses 31 and 32 and the communication pipe 51 have dimensional variations. At this time,
Since the outer corner portions 52a linearly pressed against the bottom surfaces 31a and 32a are used for sealing, it is possible to perform more reliable sealing.

(Other Embodiments) Next, embodiments other than the above embodiments will be listed. In the first embodiment, the communication pipe 33 is elastically deformed so as to be expanded in diameter by the pressure applied from the high-pressure fuel supplied to the fuel supply passages 18 and 22, and the outer peripheral surface 33b is expanded into the expanded diameter recesses 31 and 32. It is brought into close contact with the inner peripheral surfaces 31b and 32b. Then, the bottom surfaces 31a and 32a of each of the bottom surfaces 31a, 32a
Without contacting the bottom surfaces 31a, 32a of the 1, 32,
The fuel supply passages 18 and 22 are sealed between the both end surfaces 11a and 14a. Even with such a configuration, the effects described in (1) and (2) above can be obtained.

In the second embodiment, the communication pipe 43 is
The outer peripheral surfaces 43a of both ends are expanded by the diameter expanding elastic deformation of the central portion by sandwiching both ends in the axial direction in the axial direction and the overall diameter expanding elastic deformation by the pressure applied from the high pressure fuel. The recesses 41 and 42 are pressed against the inner peripheral edges of the bottom surfaces 41a and 42a. Then, both fuel supply passages 18, 22 are connected to both end surfaces 11a, 14a without pressing the outer peripheral surface 43a at the center thereof to the inner peripheral surfaces 41b, 42b on the opening side of each of the expanded diameter recesses 41, 42. To be sealed. Even with such a configuration, the effect described in (4) above can be obtained.

In the third embodiment, the communication pipe 51 is
The outer corner portions 52a of both the peripheral end faces 52 are formed into the diameter-increasing concave portions 31, 32, respectively.
By being in contact with the bottom surfaces 31a and 32a and being sandwiched in the axial direction, the center portion thereof is elastically deformed so as to expand its diameter, and the outer corner portion 52a is pressed against the bottom surfaces 31a and 32a. The outer peripheral surface 51a of the central portion is not pressed against the opening-side peripheral edges of the inner peripheral surfaces 31b and 32b of the diameter-enlarged recesses 31 and 32, and both fuel supply passages 18 and 22 have both end surfaces 1
The space between 1a and 14a is sealed. Even with such a configuration, the effect described in (5) above can be obtained.

In the first to third embodiments, the second fuel supply passage 2 is provided between the intermediate member 14 and the nozzle body 15.
You may implement in the connection structure which connects 2 and the 3rd fuel supply passage 26.

In the first to third embodiments, the injector may be of a type that does not include an intermediate member and only the nozzle body is fastened and fixed to the holder body by the retaining nut.

The communication pipes 33, 43, 51 may be integrally formed of engineering plastic. The connection structure of the fuel supply passage in the injector of the common rail type fuel injection system of the diesel engine is not limited to the connection structure of the fuel supply passage in the injector of the fuel injection pump type fuel injection system.

Not limited to the injector for the direct injection type engine, it may be embodied as a connection structure of the fuel supply passage in the injector for the auxiliary combustion chamber type engine. Not limited to the connection structure of the fuel supply passage in the injector, it may be embodied in a supply pump that supplies high-pressure fuel to the common rail or a connection structure of the fuel supply passage in the fuel injection pump.

It may be embodied as a connection structure of the fuel supply passage in the unit injector. The structure is not limited to the connection structure of the fuel supply passage in the constituent elements of the diesel engine, but may be embodied in the connection structure of the fuel supply passage in the injector of the fuel injection system of the direct fuel injection type gasoline engine.

The structure is not limited to the fuel passage connecting structure in the constituent devices of the fuel supply system for the vehicle engine, but may be embodied in a connecting structure used in various devices having a fluid passage for guiding a fluid such as fuel.

Hereinafter, the technical idea understood from each of the above-mentioned embodiments will be described together with its effects. (1) In the invention according to claim 3, the fluid passage connection structure is characterized in that the communication pipe is formed in a substantially bellows shape in a side view.

(2) In the invention according to claim 5 or 6, the fluid passage connecting structure is characterized in that the communication pipe is formed in a substantially Japanese drum shape in a side view. (3) The invention according to claim 7, wherein the engine is a diesel engine and the fuel injector is for a diesel engine.

(4) In the invention according to any one of claims 1 to 7, the fluid passage connecting structure is characterized in that the communication pipe is integrally formed of stainless steel.

[0075]

According to the inventions of claims 1 to 6, the fluid passages are communicated with each other by the enlarged diameter recesses provided in the respective passage forming members and the communication pipes held by both the enlarged diameter recesses. Therefore, the processing and assembly of each passage forming member can be made easier. Further, the size required in the radial direction can be further reduced.

In addition, according to the invention described in claims 7 and 8, in the fuel injector for a diesel engine, the holder body in which the fuel supply passage is provided separately, and the holder body is tightened and fixed by the retaining nut. The intermediate member or the nozzle body can be processed and assembled more easily. Also,
The size required in the radial direction can be made smaller.

[Brief description of drawings]

FIG. 1A is a schematic vertical sectional view showing the connection structure of the first embodiment, and FIG. 1B is a schematic plan sectional view taken along the line AA.

FIG. 2 is a schematic vertical sectional view showing an injector.

FIG. 3 is a schematic sectional view of an essential part of an injector showing a connection structure of a fuel supply passage.

FIG. 4A is a plan view showing the enlarged diameter portion, and FIG. 4B is a longitudinal sectional view of the same.

FIG. 5A is a front view showing a communication pipe, and FIG. 5B is a side view in the same partially broken state.

FIG. 6A is a schematic vertical sectional view showing an assembled state,
(B) is a similar BB line model plane sectional view.

7A is a schematic vertical sectional view showing the connection structure of the second embodiment, and FIG. 7B is a schematic plan sectional view taken along line C-C of FIG.

FIG. 8A is a plan view showing the enlarged diameter portion, and FIG.

9 (a) is a front view showing the communication pipe, and FIG. 9 (b) is a side view in the same partially broken state.

FIG. 10A is a schematic vertical sectional view showing the connection structure of the third embodiment, and FIG. 10B is a schematic plan sectional view taken along line D-D of FIG.

11 (a) is a front view showing the communication pipe, and FIG. 11 (b) is a side view in the same partially broken state.

FIG. 12 (a) is a schematic vertical sectional view of an essential part showing a conventional injector, and FIG. 12 (b) is an enlarged view of part E.

[Explanation of symbols]

10 ... Fuel injector, 11 ... Holder body as passage forming member, 11a ... Lower end surface as abutting end surface, 1
4 ... Intermediate member as passage forming member, 14a ... Upper end surface as abutting end surface, 16 ... Lower retaining nut, 18
... 1st fuel supply passage as fluid passage, 22 ... 2nd fuel supply passage, 31 ... diameter expansion concave part, 31a ... bottom surface as inner surface 32 ... diameter expansion recess 32a ... bottom surface as inner surface,
33 ... Communication pipe, 33a ... Peripheral end surface (of end portion) as outer surface, 41 ... Expanded diameter recess, 41a ... Bottom surface as inner surface, 41
b ... Inner corner portion, 42 ... Expanded diameter recess, 42a ... Bottom surface as inner surface, 42b ... Inner corner portion, 43 ... Communication pipe, 43a ... Outer surface as outer surface, 51 ... Communication tube, 51a ... Outer surface as outer surface , 52 ... Similarly, the peripheral end surface (of the end portion), 52a ... Outer corner portion.

Claims (8)

[Claims] 1. Two passage forming members, each having a fluid passage, are held in a state in which abutting end faces of the passage forming members where the fluid passage opens are in contact with each other.
A connection structure of fluid passages in which fluid passages are connected to each other between both passage formation members, wherein each passage formation member is provided with a diameter-increasing concave portion that forms an opening side end portion of the fluid passage, A communication pipe for connecting the two fluid passages is held by the two diameter-increasing recesses that are communicated with each other in a state where the contact end surfaces are in contact with each other, and the communication pipe has an outer surface thereof having the diameter-increasing recesses. The fluid passage connecting structure, wherein the fluid passages are communicated with each other in a state of being pressed against the inner surfaces of the fluid passages, and the fluid passages communicated with each other are sealed between the contact end surfaces. 2. The communication pipe is elastically deformed by a pressure applied from a fluid supplied to each of the fluid passages, and an outer surface of the communication pipe is brought into pressure contact with an inner surface of each of the enlarged diameter recesses. The connection structure of the fluid passage described. 3. The communicating pipe is elastically deformed so as to be expanded in diameter so as to be expanded in the axial direction, and each end portion in the axial direction is respectively against the bottom surface of each expanded recess. The connection structure of the fluid passage according to claim 2, wherein the connection structure is pressure-contacted. 4. The communicating pipe is elastically deformed by being sandwiched in the axial direction by the both passage forming members, and its outer surface is brought into pressure contact with the inner surface of each of the radially expanded recesses. The connection structure of the fluid passage described. 5. The fluid passage connection structure according to claim 4, wherein the communication pipe presses each end in the axial direction into pressure contact with the bottom surface of each of the enlarged diameter recesses. 6. The communicating pipe presses each end portion in the axial direction against an inner corner portion of a bottom surface of each of the expanded diameter recesses, and applies pressure from a fluid supplied to each of the fluid passages. 5. The fluid passage connection structure according to claim 4, wherein the fluid passage is elastically deformed so as to be expanded in diameter, and the both end portions are brought into pressure contact with the inner corner portions. 7. The both passage forming members are a holder body of a fuel injector for an engine and an intermediate member or a nozzle body which is fastened and fixed to the holder body by a retaining nut, and the communication pipe is the holder body. Held by the diameter-increasing concave portion that forms the opening-side end portion of the fuel supply passage, and the diameter-increasing concave portion that forms the opening-side end portion of the fuel supply passage that is provided in the intermediate member or the nozzle body. The fluid passage connection structure according to any one of claims 1 to 6, wherein 8. A fuel injector comprising the fluid passage connecting structure according to claim 7.