JP3020535U - Failure of high pressure fluid passage to high pressure fluid cavity - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] To eliminate the concentration of tensile stress in the poppet valve inlet passage. [Structure] The method of producing the first and second high-pressure passages 62, 68 connected at an intersection is such that the first wall 64 forming the first passage 62 is formed and the second passage is formed at the intersection without applying pressure. Forming the second wall 70 defining the second passage 68 to have an elongated cross section having a major axis transverse to the longitudinal axis 66 of the first passage 62.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates generally to high pressure devices, and more particularly to fuel injectors having first and second high pressure passages.

[0002]

[Prior art]

 The fuel injector generally includes a valve body having a poppet valve inlet passageway that communicates with a poppet bore formed in the valve body. These poppet valve inlet passages and poppet bores are typically formed in the valve body by electrolytic machining (ECM), electrical discharge machining (EDM), or drilling. Conventionally, the fuel injector's poppet valve inlet passage typically has a circular cross-section when viewed perpendicular to the central longitudinal axis of the poppet valve inlet passage. In operation, fuel is delivered to the poppet bore through the poppet valve inlet passageway at high pressure, for example, about 138 MPa (20,000 p.s.i.) or higher. This pressure exerts a force on the walls that form the poppet bore and poppet valve inlet passages, which cause these walls to expand and stretch radially, causing internal stresses (known as hoop stresses) to occur therein. Will occur. At the intersection of the wall of the poppet valve inlet passage and the wall of the poppet bore, hoop stress stretches the cross section of the poppet valve inlet passage in a direction perpendicular to the longitudinal axis of the poppet bore, so that the cross section of the inlet passage is parallel to the longitudinal axis of the poppet bore. It will shrink in any direction. As a result, the upper and lower ends of the poppet valve inlet passage have a small radius of curvature, so that the tensile stress is largely concentrated. This tensile stress weakens the valve body, which may eventually cause fatigue of the structure or its damage or destruction.

[0003]

[Problems to be solved by the device]

 The present invention seeks to solve the above problems.

[0004]

According to one aspect of the present invention, a method of producing first and second high pressure passages connected at an intersection includes forming a first wall forming a first passage and applying no pressure. And forming the second wall forming the second passage such that the second passage at the intersection has an elongated cross section having a long axis in a direction transverse to the longitudinal axis of the first passage. The second passage is preferably oval in cross-section at the intersection and has a longitudinal axis substantially perpendicular to the longitudinal axis of the first passage. In addition, the portion of the second passage extending from the intersection also preferably has an elongated cross section with the major axis oriented transverse to the longitudinal axis of the first passage in the absence of pressure. In another aspect of the present invention, the high-pressure device has a first wall forming a first passage and a second wall forming a second passage connected to the first passage at an intersection. In the unpressurized state, the second passage has an elongated cross-section near the intersection and has a major axis generally transverse to the longitudinal axis of the first passage. The long axis of the cross section of the second passage is preferably substantially perpendicular to the longitudinal axis of the first passage. It is also preferred that the second passage has its longitudinal axis substantially perpendicular to the longitudinal axis of the first passage and has an elliptical cross section near the intersection.

In yet another aspect of the invention, a fuel injector includes a first wall defining a poppet bore and a second wall defining a poppet valve inlet passageway that connects with the poppet bore at an intersection. Preferably, the poppet bore is circular in cross section, and in the unpressurized state, the poppet valve inlet passageway is oval in cross section near the intersection. The longitudinal axis of the poppet valve inlet passage is preferably substantially perpendicular to the longitudinal axis of the poppet bore.

[0006]

【Example】

 Referring initially to FIG. 1, a fuel injector 20 includes a three-way poppet valve that includes a valve body 24 and a valve element or poppet disposed within a cylindrical poppet bore 28 formed in the valve body 24. It consists of 26. Poppet 26 is coupled to and is actuated by armature 30 of solenoid 32. The armature 30 is normally (as viewed in FIG. 1) urged downward by a vane 34. Upon energizing solenoid 32, poppet 26 moves upward in poppet bore 28. Referring to FIG. 2, poppet bore 28 is centered within valve body 24 by a wall 40 and has a longitudinal axis 42. The valve body 24 also includes a poppet valve inlet passage 44 defined by the wall 46. Fuel is delivered to the poppet bore 28 through the poppet valve inlet passage 44 at a high pressure of, for example, about 138 MPa (20,000 p.s.i.) or higher. The poppet bore 28 and poppet valve inlet passage 44 are formed in the valve body 24 in a conventional manner using, for example, electrolytic machining (ECM), electrical discharge machining (EDM) techniques. 2-4 show a conventional prior art design, where the poppet bore 28 and the poppet valve inlet passage 44 of the valve body 24 are circular in cross section when no pressure is applied to the valve body 24. When the fuel is delivered to the poppet bore 28 at high pressure, the fuel exerts a force on the wall 40 forming the poppet bore 28 and the wall 46 forming the poppet valve inlet passage 44. The arrow 48 indicates the direction of the force on the wall 40. These forces result in tensile stresses on the walls 40 and 46. The tensile stress is most concentrated in the upper and lower portions 50,52 of the poppet valve inlet passage 44 at the intersection with the poppet bore 28 (as shown in FIGS. 2-4). This high stress concentration will cause structural fatigue and even fracture of the valve body 24 when fuel is delivered to the poppet bore 28 at high pressure.

The effect of stress on the wall of the poppet valve inlet passage 44 at high pressure is best shown in FIG. 3 where the normally circular cross section of the poppet valve inlet passage 44 extends non-circularly. , The long axis is perpendicular to the longitudinal axis 42 of the poppet bore 28. As shown in FIG. 3, the poppet valve inlet passage 44 extends so that it is adjacent to the intersection of the poppet bore 28 and the poppet valve inlet passage 44, and the poppet valve inlet passage 44 is located above and below the poppet valve inlet passage 44. Deflection of the walls that make up 44 occurs. The effect of this expansion of the shape of the poppet valve inlet passage 44 is shown in FIG. 4, where the cross section of the poppet valve inlet passage 44 is shown under no pressure (solid line) and under pressure (dashed line). By forming the poppet valve inlet passage 44 such that its longitudinal axis is substantially perpendicular to the longitudinal axis 42 of the poppet bore 28, this undesirable effect is reduced, but not eliminated. With reference to FIGS. 5-9, the valve body 60 of the present invention includes a poppet bore 62 formed of a wall 64 and having a longitudinal axis 66, and a poppet valve inlet passage 68 formed of wall 70 and having a longitudinal axis 72. As shown in FIG. 6, the poppet valve inlet passage 68 gradually connects to the poppet bore 28 at a transition region 74 that smoothly curves to the poppet bore 62. The poppet valve inlet passage 68 preferably has an elongated cross section with the major axis generally perpendicular to the longitudinal axis 66 of the poppet bore 62 in the absence of pressure on the valve body 60. As a result, as shown in FIG. 7, the upper and lower portions 76, 78 of the poppet valve inlet passage 68 have a radius of curvature of almost infinity, and the stress concentration in these portions of the poppet valve inlet passage 68 is It is smaller than the corresponding portion of the poppet valve inlet passage 44 of the conventional valve body 24. The stress concentration in the upper and lower portions of the poppet valve inlet passage 68 is further reduced by forming the poppet valve inlet passage 68 so as to intersect the poppet bore 62 at approximately 90 °. In other words, the longitudinal axis 72 of the poppet valve inlet passage 68 is substantially perpendicular to the longitudinal axis 66 of the poppet bore 62. This reduction in stress concentration reduces the likelihood that the valve body 60 will suffer structural fatigue, failure or fracture the next time fuel is delivered at high pressure to the poppet bore 62.

A portion of the poppet valve inlet passage 68 extending from the intersection of the poppet valve inlet passage 68 with the poppet bore 62 is preferably long in cross section so that stress concentration of the valve body 60 is sufficiently reduced to prevent its destruction. Referring to FIG. 8, a force is exerted on the wall of the valve body 60 during the periodic delivery of high pressure fuel through the poppet valve inlet passage 68 to the poppet bore 62, causing pulsating hoop stress on the wall of the valve body 60. However, the stress concentration factor of the oval poppet valve inlet passage 68 is lower than that of the conventional circular passage. Therefore, the flat portions 76, 78 of the poppet valve inlet passage 68 do not distort appreciably due to the hoop stresses that occur under pressure and the valve body 60 is less prone to fatigue failure or failure. The arrow 80 shows the direction of the force exerted on the wall 64. FIG. 9 shows a cross section of the poppet valve inlet passage 68 in a state where no pressure is applied (solid line) and a state where pressure is applied (dashed line), and shows that the valve body 60 has less distortion than the conventional valve body 24. . The embodiments of the fuel injector of the present invention have been described above. However, the present invention can be incorporated in an example where one high pressure passage intersects with another high pressure passage. Since the detrimental effects of hoop stress can be reduced by the present invention, high pressure equipment can be designed to withstand greater pressures, or can be made smaller without sacrificing equipment durability. Alternatively it can be made of a weaker and therefore cheaper material.

Many modifications and alternatives will be apparent to those skilled in the art from the foregoing. Therefore, this description is given for the sake of example, to show those skilled in the art the best mode of carrying out the invention. Without departing from the spirit of the present invention, the details of the structure can be changed sufficiently, and all changes falling within the scope of the utility model registration claim are included in the present invention.

[Brief description of drawings]

1 is an elevational view in section showing a portion of a fuel injector in which the present invention may be used.

FIG. 2 is a perspective view of a portion of a conventional valve body having a circular poppet valve inlet passage in the unpressurized state.

FIG. 3 is a perspective view of a portion of the valve body of FIG. 2 under pressure.

4 is an elevational view of a portion of the inlet passage of the valve body of FIG. 2 with and without pressure applied.

FIG. 5 is a general perspective view of a fragment of a valve body incorporating the present invention.

6 is a cross-sectional view of the valve body taken along line 6-6 of FIG.

FIG. 7 is a perspective view of a portion of the valve body of the present invention in the absence of pressure.

8 is a perspective view of a portion of the valve body of FIG. 7 under pressure.

9 is an elevational view of a portion of the inlet passage of the valve body of FIG. 7 with and without pressure applied.

[Explanation of symbols]

 20 ・ ・ Fuel injector 22 ・ ・ Three-way poppet valve 24 ・ ・ Valve body 26 ・ ・ Poppet 28 ・ ・ Poppet bore 30 ・ ・ Pole arm 32 ・ ・ Solenoid 34 ・ ・ Spring 40 ・ ・ Wall 42 ・ ・ Longitudinal shaft 44 ・・ Poppet valve inlet passage 46 ・ ・ Wall 48 ・ ・ Arrow 50 ・ ・ Upper part 52 ・ ・ Lower part 60 ・ ・ Valve body 62 ・ ・ Poppet bore 64 ・ ・ First wall 66 ・ ・ Longitudinal axis 68 ・ ・ Poppet valve Inlet passage 70 .. Second wall 72 .. Longitudinal axis 74 .. Transition area 76 .. Upper part 78 .. Lower part 80 .. Arrow

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[Procedure amendment]

[Submission date] July 20, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Scope of utility model registration request

[Correction method] Change

[Correction content]

[Scope of utility model registration request]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location F16L 55/04 (72) Creator Ronald Dee Signogle Illinois, USA 61614 Pioria West Centennial Drive 1023

Claims (14)

[Scope of utility model registration request] 1. A method for producing first and second high-pressure fluid passages (62, 68) connected at an intersection, wherein a first wall (64) constituting the first passage (62) is formed and no pressure is applied. In the state, the second passage (68) at the intersection has a long and narrow cross section having a long axis in a direction transverse to the longitudinal axis (66) of the first passage (62).
A method comprising the steps of forming a second wall (70) that constitutes (68). 2. Method according to claim 1, characterized in that the second passage (68) has an elliptical cross section at the intersection. 3. A second passage (68) having a longitudinal axis (72) substantially perpendicular to the longitudinal axis (66) of the first passage (62). Method. 4. The second passage (68) extending from the intersection.
A part of the main passage is in a state where no pressure is applied and the major axis is the first passage.
A method according to claim 1, characterized in that it has an elongated cross section oriented transversely to the longitudinal axis (66) of (62). 5. The method of claim 4, wherein a portion of the second passage (68) has an elliptical cross section. 6. A method of forming first and second high pressure fluid passages (62, 68) connected at an intersection, wherein a first wall (64) constituting the first passage (62) is formed and no pressure is applied. The second passage at the intersection in the state
The second passage so that the (68) has an elliptical cross section having a major axis in a direction substantially perpendicular to the longitudinal axis (66) of the first passage (62);
A method comprising the steps of forming a second wall (70) defining a passageway (68). 7. The second passage (68) extending from the intersection.
A part of the main passage is in a state where no pressure is applied and the major axis is the first passage.
7. A method according to claim 6, characterized in that it has an elliptical cross section oriented substantially perpendicular to the longitudinal axis (66) of (62). 8. The method of claim 6, wherein the second passage (68) has a longitudinal axis (72) substantially perpendicular to the longitudinal axis (66) of the first passage (62). Method. 9. A first wall (64) forming a first passage (62) having a longitudinal axis (66) and a second passage (68) connecting with the first passage (62) at an intersection. A second wall (70), the second passage (68) in a direction substantially transverse to the longitudinal axis (66) of the first passage (62) near the intersection in the unpressurized state. -Pressure device having an elongated cross section with the long axis of. 10. Apparatus according to claim 9, characterized in that the major axis is substantially perpendicular to the longitudinal axis (66) of the first passage (62). 11. The second passage (68) is the first passage (62).
The device of claim 9 having a longitudinal axis (72) substantially perpendicular to said longitudinal axis (66). 12. The device of claim 9, wherein said second passage (68) has an elliptical cross section near said intersection. 13. A first wall (64) constituting a poppet bore (62) having a circular cross section and a poppet valve inlet passageway (68) communicating with the poppet bore (62) at an intersection without pressure. However, the fuel injector is characterized by including a second wall (70) having an elliptical cross section near the intersection without applying pressure. 14. The poppet valve inlet passageway (68) has a longitudinal axis (72) substantially perpendicular to the longitudinal axis (66) of the poppet bore (62). Fuel injector.