JP2004308603A - Fluid injection valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluid injection valve preventing fluid leak to an injection hole during shut off of fluid injection. <P>SOLUTION: A flow passage 27 flowing fluid therethrough toward the injection hole 31 is formed, a valve body 26 surrounding an outer circumference of the flow passage 27 and having a valve seat 28 in an upper stream side of the injection hole 31 and a valve element 40 moving to a lower stream side in the flow passage 27 and shutting off injection of fluid from the injection hole 31 by abutting on the valve seat 28 are provided. A plurality of seat parts 46, 47 which are formed by abutment of the valve element 40 and the valve seat 28 is positioned with having a gap part 48 separating the valve element 40 and the valve seat 28 therebetween and mutually shifting to a flow direction X of the flow passage 27. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fluid injection valve that injects fluid such as fuel.
[0002]
[Prior art]
BACKGROUND ART Conventionally, there is known a fluid injection valve in which a valve seat is provided on an upstream side of an injection hole of a valve body that forms a flow path, and fluid injection from the injection hole is shut off by contacting a valve member with the valve seat. It is. Patent Literature 1 discloses a technique in which an outer circumferential surface of a valve member is brought into contact with an inner circumferential surface of a valve seat to form one annular seat portion extending in a circumferential direction. In this technique, in order to control the fluid injection amount with high accuracy, it is necessary to reduce fluid leakage from the upstream to the downstream of the seat portion to the injection holes. As a method of reducing fluid leakage, a method of increasing processing accuracy such as roundness or surface roughness of a portion forming a seat portion in a valve member and / or a valve seat has been considered.
[0003]
[Patent Document 1]
JP 2001-317431 A
[Problems to be solved by the invention]
However, even if the processing accuracy of the seat portion forming portion in the valve member and / or the valve seat is improved, the seat portion forming portion is deformed with the assembly of the valve member, the valve seat and the like. For this reason, a clearance may be generated in the seat portion, and fluid leakage to the injection hole may not be sufficiently reduced.
An object of the present invention is to provide a fluid injection valve that prevents fluid leakage to an injection hole when fluid injection is cut off.
[0005]
[Means for Solving the Problems]
According to the first to ninth aspects of the present invention, the valve body has a valve seat surrounding the outer periphery of the flow path on the upstream side of the injection hole, and the valve member moves in the flow path to the downstream side or the upstream side to open the valve. By contacting the seat, fluid ejection from the injection hole is shut off. The plurality of seat portions formed by the abutment between the valve member and the valve seat are positioned to be shifted from each other in the flow direction of the flow path with a gap separating the valve member and the valve seat interposed therebetween. Thereby, since the fluid is confined in the gap between the two sheet portions arranged in the flow direction, the pressure difference of the fluid on both sides in the flow direction of the downstream sheet portion of the two sheet portions is reduced, and the downstream sheet portion is reduced. Fluid hardly leaks from the clearance of the part. According to the above principle, when the fluid ejection is interrupted, it is possible to prevent the fluid from leaking from the upstream side of the most downstream sheet portion to the injection hole located downstream.
[0006]
According to the second aspect of the present invention, when the valve member moves to the side in contact with the valve seat, the upstream seat portion and the downstream seat portion are formed almost simultaneously. On the other hand, according to the third aspect of the invention, when the valve member moves to the side in contact with the valve seat, the upstream seat portion is formed before the downstream seat portion. According to the second and third aspects of the present invention, at the time of forming the downstream sheet portion, the fluid is confined in the upstream gap of the downstream sheet portion. Therefore, the effect of preventing fluid leakage in the downstream sheet portion can be reliably obtained simultaneously with the formation of the downstream sheet portion.
[0007]
According to the fourth and fifth aspects of the invention, in at least one of the valve member and the valve seat, one of the portion forming the upstream seat portion and the portion forming the downstream seat portion has higher elasticity than the other. Have. According to this configuration, it is possible to improve the liquid tightness of the sheet portion formed of the high elasticity portion, and to ensure the impact resistance of the sheet portion formed of the low elasticity portion, that is, the high rigidity portion. In particular, according to the fifth aspect of the present invention, since the portion forming the upstream sheet portion has higher elasticity than the portion forming the downstream sheet portion, the gap portion from the upstream side to the downstream side of the upstream sheet portion is provided. Makes it difficult for fuel to leak. Accordingly, it is possible to suppress an increase in pressure in the gap due to additional fuel being added to the fuel confined in the gap, and the effect of preventing fluid leakage in the downstream seat portion does not decrease.
[0008]
According to the invention described in claims 6 to 9, a plurality of annular seat portions extending in the circumferential direction are formed by the outer peripheral surface of the valve member being in contact with the inner peripheral surface of the valve seat. In particular, in the invention according to claim 7, the outer peripheral surface of the valve member is formed in a stepped cylindrical surface shape in which the diameter is gradually reduced, and the inner peripheral surface of the valve seat is formed in a conical surface shape in which the diameter is reduced at a substantially constant taper angle. Formed. On the other hand, in the invention described in claim 8, the outer peripheral surface of the valve member is formed in a spherical shape, and the inner peripheral surface of the valve seat is formed in a conical shape in which the taper angle gradually increases toward the smaller diameter side. . On the other hand, according to the ninth aspect of the present invention, the outer peripheral surface of the valve member is formed in a spherical shape, and the inner peripheral surface of the valve seat is formed in a stepped cylindrical shape whose diameter is gradually reduced. According to each of the inventions described in the seventh, eighth, and ninth aspects, it is possible to form a plurality of seat portions having the above-described effects with a simple configuration.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 2 shows a fuel injection valve as a fluid injection valve according to the first embodiment of the present invention. In the fuel injection valve 10 of the first embodiment, the cylindrical member 11, the fixed core 15, the movable core 16, the needle 40 as a valve member, and the valve body 26 each have a flow path through which fuel flows downward from above in FIG. The inner peripheral wall is formed.
[0010]
The cylindrical member 11 is formed in a cylindrical shape, and has a first magnetic part 12, a non-magnetic part 13, and a second magnetic part 14 in this order from the injection hole 31 side. The non-magnetic portion 13 prevents the magnetic flux from short-circuiting between the first magnetic portion 12 and the second magnetic portion 14. The fixed core 15 is formed of a magnetic material into a cylindrical shape, and is coaxially fixed to the inner peripheral wall of the cylindrical member 11. The movable core 16 is formed of a magnetic material into a cylindrical shape, and is accommodated coaxially on the inner peripheral side of the tubular member 11. The movable core 16 is capable of reciprocating in the axial direction on the downstream side of the fixed core 15. One end of the spring 17 is locked to the fixed core 15, and the other end of the spring 17 is locked to the movable core 16. The spring 17 urges the movable core 16 toward the non-fixed core side, that is, toward the downstream side. The filter 18 is fixed to the inner peripheral wall of the tubular member 11 on the upstream side of the fixed core 15, and removes foreign matter in the fuel supplied to the fuel injection valve 10 from a fuel transfer pipe (not shown).
[0011]
A spool 20 is fixed to the outer peripheral wall of the tubular member 11, and a coil 21 is wound around the spool 20. The outer peripheral sides of the spool 20 and the coil 21 are covered with a resin-molded connector 22. Terminal 23 is embedded in connector 22 and is electrically connected to coil 21. When the coil 21 is energized through the terminal 23, a magnetic attractive force acts between the fixed core 15 and the movable core 16.
[0012]
As shown in FIGS. 1 and 2, the valve body 26 is formed of a metal material and has a cylindrical shape, and is coaxially fixed to an inner peripheral wall at a downstream end of the cylindrical member 11. The injection hole plate 30 is formed in a cylindrical shape with a bottom and is coaxially fixed to the outer peripheral wall of the valve body 26. A plurality of injection holes 31 penetrate the vicinity of the center of the bottom wall of the injection hole plate 30. The flow path 27 formed by the inner peripheral wall of the valve body 26 communicates with each of the injection holes 31 at the downstream end, and flows the fuel toward each of the injection holes 31. The valve body 26 forms a valve seat 28 at an inner peripheral wall portion surrounding the outer periphery of the downstream end of the flow path 27, and the valve seat 28 is located upstream of each injection hole 31. The inner peripheral surface 29 of the valve seat 28 is formed in a conical shape whose diameter decreases at a substantially constant taper angle θ toward the downstream side of the flow path 27.
[0013]
The needle 40 is entirely formed of a metal material, has a cylindrical shape with a bottom, and is accommodated coaxially on the inner peripheral side of the valve body 26 and the cylindrical member 11. The needle 40 is joined to the movable core 16 on the side opposite to the bottom wall, and the needle 40 can reciprocate in the axial direction integrally with the movable core 16. A plurality of through holes 41 penetrate the side wall of the needle 40, and the fuel flows from the flow path in the needle 40 through each through hole 41 into the flow path 27.
[0014]
The bottom wall 42 of the needle 40 projects into the flow path 27 on the inner peripheral side of the valve seat 28. The outer peripheral surface 43 of the bottom wall portion 42 is formed in the shape of a stepped cylinder whose diameter is gradually reduced toward the downstream side of the flow path 27, and two boundary lines between the constant diameter portion and the diameter change portion are provided. Edge portions 44 and 45 are formed. The edge portion 44 and the edge portion 45 are arranged in a coaxial circular shape with the latter having a smaller diameter than the former, and are shifted from each other in the flow direction X of the flow path 27. As the needle 40 moves to the downstream side, the edge portion 44 and the edge portion 45 abut on the inner peripheral surface 29 of the valve seat 28 at a position shifted in the flow direction X at the same time. The upstream seat portion 46 is formed by the contact portion between the edge portion 44 and the inner peripheral surface 29, and the downstream seat portion 47 is formed by the contact portion between the edge portion 45 and the inner peripheral surface 29, respectively. It is formed in an annular shape extending in the circumferential direction. In a state where the sheet portions 46 and 47 are formed together, a gap portion 48 that separates the outer peripheral surface 43 and the inner peripheral surface 29 is formed between the sheet portions 46 and 47 in an annular shape. The formation of the seat portions 46 and 47 blocks communication between the flow path 27 upstream of the upstream seat portion 46 and each of the injection holes 31 downstream of the downstream seat portion 47.
[0015]
In the fuel injection valve 10 described above, when energization of the coil 21 is turned on and a magnetic attraction force is generated between the fixed core 15 and the movable core 16, the movable core 16 together with the needle 40 resists the urging force of the spring 17. And move upstream. As a result, the respective edge portions 44 and 45 of the needle 40 are separated from the inner peripheral surface 29 of the valve seat 28, so that fuel is injected from the respective injection holes 31.
[0016]
On the other hand, when the power to the coil 21 is turned off and the magnetic attraction between the cores 15 and 16 disappears, the movable core 16 and the needle 40 move downstream by the urging force of the spring 17. As a result, the respective edge portions 44 and 45 of the needle 40 abut on the inner peripheral surface 29 of the valve seat 28 to form the respective seat portions 46 and 47, so that the fuel injection from the respective injection holes 31 is shut off. In the fuel injection valve 10 in which the seats 46 and 47 are formed almost simultaneously, the fuel is confined in the gap 48 sandwiched between the seats when the seat is formed. Therefore, the pressure difference of the fluid on both sides in the flow direction of the downstream sheet portion 47 (that is, the upstream side and the downstream side) is substantially eliminated. Since the amount of fuel leakage from the clearance of the downstream seat portion 47 is proportional to the pressure difference between both sides of the downstream seat portion 47 in the flow direction, in the fuel injection valve 10 where the pressure difference is substantially eliminated, Fuel leakage from the upstream side to each of the injection holes 31 on the downstream side is prevented. Therefore, the fuel injection amount from the injection hole 31 can be controlled with high accuracy.
[0017]
When the needle 40 moves downstream, the upstream edge portion 44 may abut the inner peripheral surface 29 of the valve seat 28 before the downstream edge portion 45. In this case, since the upstream sheet portion 46 is formed before the downstream sheet portion 47, the fuel is confined in the gap portion 48 at the time of formation of the downstream sheet portion 47, and the same effect as described above is obtained. can get.
[0018]
(Second embodiment)
FIG. 3 shows a fuel injection valve as a fluid injection valve according to a second embodiment of the present invention. Components substantially the same as those in the first embodiment are denoted by the same reference numerals.
In the fuel injection valve 50 of the second embodiment, the upstream edge portion 44 is formed of an elastic material such as rubber, and has higher elasticity than the downstream edge portion 45 formed of a metal material. In other words, the rigidity of the downstream edge 45 is higher than the rigidity of the upstream edge 44. The timing at which the upstream edge portion 44 and the downstream edge portion 45 come into contact with the inner peripheral surface 29 of the valve seat 28 is set so that they are substantially simultaneous, but the former is earlier than the latter. May be set.
[0019]
In such a fuel injection valve 50, the liquid-tightness is improved in the upstream seat portion 46 formed by the highly elastic edge portion 44, and thereby, the gap is formed from the upstream side of the upstream seat portion 46 to the downstream side thereof. Fuel leakage is reduced. For this reason, it is possible to suppress an increase in the pressure in the gap portion 48 due to the additional fuel added to the fuel confined in the gap portion 48, and the effect of preventing the fuel leakage in the downstream seat portion 47 does not decrease. In addition, in the downstream seat portion 47 formed by the highly rigid edge portion 45, durability (impact resistance) against impact when the needle 40 abuts on the valve seat 28 can be secured.
Note that the downstream edge portion 45 may be formed of an elastic material, and the upstream edge portion 44 may be formed of a metal material having lower elasticity than the edge portion 45.
[0020]
(Third embodiment)
FIG. 4 shows a fuel injection valve as a fluid injection valve according to a third embodiment of the present invention. Components substantially the same as those in the first embodiment are denoted by the same reference numerals.
In the fuel injection valve 60 of the third embodiment, the bottom wall portion of the needle 40 is constituted by the ball member 62 whose outer peripheral surface 63 is spherical. In the valve body 26, the inner peripheral surface 29 of the valve seat 28 is formed in a conical shape whose taper angle discretely increases to θ1 and θ2 toward the downstream side of the flow path 27. That is, the inner peripheral surface 29 is formed in a conical shape whose taper angle gradually increases toward the smaller diameter side, and two seating surfaces 64 and 65 are formed on both sides of the boundary line where the taper angle changes. ing. The seating surface 64 whose taper angle is θ1 and the seating surface 65 whose taper angle is θ2 larger than θ1 are shifted from each other in the flow direction X of the flow path 27. As the needle 40 moves downstream, the outer peripheral surface 63 of the ball member 62 comes into contact with each of the seating surfaces 64 and 65 at a position shifted in the flow direction X. In the present embodiment, the outer peripheral surface 63 abuts the seat surfaces 64 and 65 almost simultaneously, but the outer peripheral surface 63 may abut the seat surface 64 before the seat surface 65. The upstream seat portion 66 is formed by the contact portion between the seating surface 64 and the outer peripheral surface 63, and the downstream seat portion 67 is formed by the contact portion between the seating surface 65 and the outer peripheral surface 63, respectively, in the circumferential direction of the needle 40 and the valve seat 28. And is formed in an annular shape. In a state where the seat portions 66 and 67 are formed together, a gap portion 68 that separates the seating surfaces 64 and 66 from the outer peripheral surface 63 is formed between the seat portions 66 and 67 in an annular shape.
[0021]
In such a fuel injection valve 60, when the seat portions 66 and 67 are formed, communication between the flow path 27 upstream of the upstream seat portion 66 and each injection hole 31 downstream of the downstream seat portion 67 is established. Since the fuel injection is cut off, the fuel injection from each injection hole 31 is cut off. In the fuel injection valve 60 in which the seats 66 and 67 are formed almost simultaneously, the fuel is confined in the gap 68 sandwiched between the seats when the seat is formed. Thereby, the pressure difference of the fluid on both sides in the flow direction of the downstream seat portion 67 is substantially eliminated, so that the fuel leakage from the upstream side of the downstream seat portion 67 to each of the injection holes 31 on the downstream side is prevented.
[0022]
(Fourth embodiment)
FIG. 5 shows a fuel injection valve as a fluid injection valve according to a fourth embodiment of the present invention. Components substantially the same as those in the first embodiment are denoted by the same reference numerals.
In the fuel injection valve 70 of the fourth embodiment, the bottom wall portion of the needle 40 is constituted by the ball member 72 whose outer peripheral surface 73 is spherical. In the valve body 26, the inner peripheral surface 29 of the valve seat 28 is formed in a stepped cylindrical shape whose diameter gradually decreases toward the downstream side of the flow path 27, and has a constant diameter portion and a diameter change portion. , Two edge portions 74 and 75 are formed. The edge portion 74 and the edge portion 75 are arranged in a coaxial circle with the latter having a smaller diameter than the former, and are shifted from each other in the flow direction X of the flow path 27. As the needle 40 moves downstream, the outer peripheral surface 73 of the ball member 72 comes into contact with each of the edge portions 74 and 75 at a position shifted in the flow direction X. In the present embodiment, the outer peripheral surface 73 contacts the edge portions 74 and 75 almost simultaneously. However, the outer peripheral surface 73 may contact the edge portion 74 before the edge portion 75. The contact portion between the edge portion 74 and the outer peripheral surface 73 causes the upstream seat portion 76, and the contact portion between the edge portion 75 and the outer peripheral surface 73 causes the downstream seat portion 77 to rotate in the circumferential direction of the needle 40 and the valve seat 28. And is formed in an annular shape. In a state where the sheet portions 76 and 77 are formed together, a gap portion 78 that separates the inner peripheral surface 29 and the outer peripheral surface 73 is formed between the sheet portions 76 and 77 in an annular shape.
[0023]
In such a fuel injection valve 70, when the seat portions 76 and 77 are formed, the communication between the flow path 27 upstream of the upstream seat portion 76 and each of the injection holes 31 downstream of the downstream seat portion 77 is established. Since the fuel injection is cut off, the fuel injection from each injection hole 31 is cut off. In the fuel injection valve 70 in which the seats 76 and 77 are formed almost simultaneously, at the time of forming the seat, the fuel is confined in the gap 78 sandwiched between the seats. Thereby, the pressure difference of the fluid on both sides in the flow direction of the downstream seat portion 77 is substantially eliminated, so that the fuel leakage from the upstream side of the downstream seat portion 77 to each of the injection holes 31 on the downstream side is prevented.
[0024]
In this embodiment, both the edge portions 74 and 75 are formed of a metal material. However, the upstream edge portion 74 is formed of an elastic material, and the downstream edge portion 75 has lower elasticity than the edge portion 74. The same effect as in the second embodiment may be obtained by forming with the above metal material. Alternatively, the downstream edge portion 75 may be formed of an elastic material, and the upstream edge portion 74 may be formed of a metal material having lower elasticity than the edge portion 75.
[0025]
By the way, in the above-described embodiments, when the needle 40 as the valve member moves to the downstream side of the flow path 27, the needle 40 comes into contact with the fuel injection valve 10, 50, 60, 70 which contacts the valve seat 28. The invention has been applied. On the other hand, the present invention may be applied to a fluid injection valve that comes into contact with a valve seat when the valve member moves to the upstream side.
In the above-described embodiments, two sheet portions according to the present invention are formed, but three or more sheet portions according to the present invention may be formed.
[Brief description of the drawings]
FIG. 1 is an enlarged sectional view showing a main part of a fuel injection valve according to a first embodiment of the present invention.
FIG. 2 is a sectional view showing a fuel injection valve according to the first embodiment of the present invention.
FIG. 3 is an enlarged sectional view showing a main part of a fuel injection valve according to a second embodiment of the present invention.
FIG. 4 is an enlarged sectional view showing a main part of a fuel injection valve according to a third embodiment of the present invention.
FIG. 5 is an enlarged sectional view showing a main part of a fuel injection valve according to a fourth embodiment of the present invention.
[Explanation of symbols]
10, 50, 60, 70 Fuel injection valve (fluid injection valve)
26 valve body 27 flow path 28 valve seat 29 inner peripheral surface 30 injection hole plate 31 injection hole 40 needle (valve member)
42 Bottom wall 43 Outer peripheral surfaces 44, 45, 74, 75 Edges 46, 47, 66, 67, 76, 77 Seats 48, 68, 78 Gaps 62, 72 Ball members 63, 73 Outer peripheral surfaces 64, 65 Surface X Flow direction θ, θ1, θ2 Taper angle

Claims (9)

A valve body having a flow path through which a fluid flows toward the injection hole and having a valve seat surrounding the outer periphery of the flow path on the upstream side of the injection hole;
A valve member that shuts off the ejection of the fluid from the injection hole by moving in the flow path to the downstream side or the upstream side and abutting on the valve seat,
With
A plurality of seat portions formed by the valve member and the valve seat in contact with each other are located offset from each other in the flow direction of the flow path with a gap portion separating the valve member and the valve seat therebetween. A fluid injection valve characterized by the above-mentioned. 2. The fluid injection valve according to claim 1, wherein when the valve member moves to a side in contact with the valve seat, the upstream seat portion and the downstream seat portion are formed substantially simultaneously. 3. . 2. The fluid injection valve according to claim 1, wherein when the valve member moves to a side that comes into contact with the valve seat, the upstream seat portion is formed earlier than the downstream seat portion. 3. In at least one of the valve member and the valve seat, one of a portion forming the seat portion on the upstream side and a portion forming the seat portion on the downstream side has higher elasticity than the other. Item 4. The fluid injection valve according to item 1, 2 or 3. The fluid according to claim 4, wherein at least one of the valve member and the valve seat has a higher elasticity at a portion forming the seat portion on the upstream side than a portion forming the seat portion on the downstream side. Injection valve. The plurality of annular seat portions extending in the circumferential direction are formed by abutting an outer peripheral surface of the valve member and an inner peripheral surface of the valve seat. 3. The fluid injection valve according to item 1. An outer peripheral surface of the valve member is formed in a stepped cylindrical surface having a diameter gradually reduced, and an inner peripheral surface of the valve seat is formed in a conical surface with a reduced diameter at a substantially constant taper angle. 7. The fluid injection valve according to claim 6, wherein: 7. The valve device according to claim 6, wherein an outer peripheral surface of the valve member is formed in a spherical shape, and an inner peripheral surface of the valve seat is formed in a conical surface in which a taper angle gradually increases toward a small diameter side. A fluid injection valve as described. 7. The fluid injection valve according to claim 6, wherein an outer peripheral surface of the valve member is formed in a spherical shape, and an inner peripheral surface of the valve seat is formed in a stepped cylindrical surface whose diameter is reduced stepwise. .

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