JP4665985B2 - Injector - Google Patents

Description

  The present invention relates to an injector that injects fuel, and more particularly to an injector that injects an injection fluid different from a working fluid for transmitting a driving force.

  2. Description of the Related Art Conventionally, an injector that ejects an ejection fluid different from a working fluid for transmitting a driving force is known. For example, in Patent Document 1, injection of a gaseous injection fluid is intermittently performed by a needle driven by hydraulic pressure of hydraulic oil. As described above, the working fluid and the jetting fluid have different characteristics such as gas and liquid, or even hydraulic fluid and fuel, even if it is liquid. As described above, in the case of an injector using working fluids and jetting fluids having different characteristics, it is necessary to prevent mixing of the working fluid and the jetting fluid.

However, when a partition member for preventing mixing between the working fluid and the jet fluid is provided, the partition member receives a force due to a pressure difference between the working fluid and the jet fluid. Therefore, the partition member is deformed by receiving a force from one to the other whenever the pressure of the working fluid or the jet fluid changes. The partition member has a problem that the strength is lowered by repeated deformation. On the other hand, when the plate thickness of the partition member is increased in order to maintain the strength, it is necessary to drive the partition member having a large plate thickness when driving the needle. As a result, there is a problem that the drive unit is enlarged and the power consumption of the drive unit is increased.
Japanese Utility Model Publication No. 63-4365

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an injector in which the deformation of the partition member is reduced and the durability is improved without increasing the size of the drive unit and increasing the power consumption. There is to do.

  In invention of Claim 1, 4 or 5, the piston member is provided. The piston member moves due to the difference between the pressure of the injection fluid received at the injection fluid pressure receiving surface and the pressure of the working fluid received at the working fluid pressure receiving surface. That is, the piston member moves to a position where the force received from the ejection fluid in the ejection fluid supply unit and the force received from the working fluid in the working fluid supply unit are balanced, and adjusts the pressure between the ejection fluid and the working fluid. Thereby, the change of the force added to the partition member which partitions off between the ejection fluid supply part and the working fluid supply part becomes small. Therefore, deformation of the partition member can be reduced, and durability of the partition member can be improved. Moreover, the plate | board thickness of a partition member is reduced by reducing the deformation | transformation of a partition member. Therefore, it is not necessary to increase the driving force of the driving unit, and it is possible to suppress an increase in the size of the driving unit and an increase in power consumption.

  In the invention according to claim 2, the piston member has the jet fluid pressure receiving surface and the working fluid pressure receiving surface having the same area. Therefore, the piston member moves to a position where the pressure of the jet fluid and the pressure of the working fluid become the same. Since the pressure of the jet fluid and the pressure of the working fluid are the same, it is difficult for one fluid to leak into the other fluid. Therefore, deformation of the partition member can be reduced, and mixing of the ejection fluid and the working fluid can be reduced.

According to a third aspect of the present invention, the piston member has a jet fluid pressure receiving surface having a smaller area than the working fluid pressure receiving surface. Thereby, a piston member balances in the position where the pressure of a jet fluid becomes high rather than a working fluid. That is, the pressure of the ejection fluid is maintained higher than the pressure of the working fluid. Therefore, the needle receives a force in either the valve closing direction or the valve opening direction by the jet fluid. For example, when force is applied to the needle from the drive unit, when the needle opens the injection hole and the injected fuel is injected from the injection hole, the injection hole is closed by increasing the pressure of the injection fluid over the working fluid. The force of the direction to be always added. Therefore, when the driving force from the driving unit to the needle is interrupted after the needle has opened the nozzle hole, the needle returns to the position where the nozzle hole is closed by the force of the jet fluid. As a result, a configuration for returning the needle to the position where the nozzle hole is closed becomes unnecessary. Therefore, the number of parts can be reduced and the structure can be simplified.
According to a sixth aspect of the present invention, the piston member is provided in a housing chamber integral with a housing member having an ejection fluid supply part and a working fluid supply part. Thereby, the piston member that adjusts the pressure difference between the jet fluid and the working fluid is accommodated in the housing. Therefore, it is possible to adjust the pressures of the ejection fluid and the working fluid without increasing the size and the structure.

Hereinafter, a plurality of embodiments of an injector by the present invention are described based on a drawing. Note that, in a plurality of embodiments, substantially the same components are denoted by the same reference numerals, and description thereof is omitted.
(First embodiment)
FIG. 2 shows a fuel injection system to which the injector according to the first embodiment of the present invention is applied. As shown in FIG. 2, the fuel injection system 100 includes an injector 10, a fuel cylinder 11, a surge tank 12, a piping part 13, and a check valve part 14. The fuel cylinder 11 stores, for example, an injection fluid serving as a fuel such as hydrogen or CNG (compressed natural gas) in a gaseous state. The piping part 13 connects between the fuel cylinder 11 and the injector 10. The surge tank 12 is provided in the middle of the piping part 13. The surge tank 12 holds the injection fluid supplied from the fuel cylinder 11 at a lower pressure than the injection fluid stored in the fuel cylinder 11. By providing the surge tank 12 having a large capacity in the middle of the piping part 13, the pressure fluctuation of the injection fluid supplied to the injector 10 is reduced. A check valve portion 14 is provided between the surge tank 12 and the fuel cylinder 11 side of the piping portion 13. The check valve portion 14 includes a check valve passage 15 and a check valve 16. The check valve 16 opens when the pressure in the surge tank 12 becomes excessive. Thereby, when the pressure of the surge tank 12 becomes excessive, the injected fluid is returned from the surge tank 12 to the fuel cylinder 11 side.

  As shown in FIG. 1, the injector 10 includes a housing 20, a needle 30, a drive unit 40, a drive force transmission unit 50, a diaphragm 60 as a partition member, and a pressure adjustment unit 70. The housing 20 includes a body 21, a spacer 22, a pipe 23 and a nozzle body 24. The body 21 is formed in a cylindrical shape, and has an accommodation hole 211 that accommodates the drive unit 40 and the drive force transmission unit 50 at the center. The accommodation hole 211 penetrates the body in the axial direction. The body 21 has a fuel supply part 25 on one outer side in the radial direction of the accommodation hole 211. The fuel supply unit 25 is supplied with an injection fluid that is fuel via the pipe unit 13. The body 21 includes a pressure adjusting unit 70 on the opposite side of the fuel supply unit 25 with the accommodation hole 211 therebetween. The body 21 has an ejection fluid hole 212 and an ejection fluid hole 213 through which the ejection fluid flows on the radially outer side of the accommodation hole 211. The jet fluid hole 212 passes through the body 21 in the axial direction, and one end thereof is connected to the fuel supply unit 25. The jet fluid hole 213 penetrates the body 21 in the axial direction, and one end thereof is connected to the pressure adjusting unit 70.

  The body 21 is in contact with the spacer 22 on the tip side, that is, on the side opposite to the fuel supply unit 25 and the pressure adjustment unit 70 in the axial direction. The spacer 22 has one end in the axial direction in contact with the body 21 and the other end in contact with the diaphragm 60. The diaphragm 60 has one end in the axial direction in contact with the spacer 22 and the other end in contact with the pipe 23. That is, the spacer 22 and the diaphragm 60 are sandwiched between the body 21 and the pipe 23. The pipe 23 holds the nozzle body 24 at the end opposite to the spacer 22. The nozzle body 24 is fixed to the end of the pipe 23. The nozzle body 24 fixed to the spacer 22, the diaphragm 60 and the pipe 23 is fixed to the body 21 by a retaining nut 26. As a result, the body 21, the spacer 22, the pipe 23 and the nozzle body 24 constitute an integral housing 20 including the diaphragm 60.

  As shown in FIG. 3, the spacer 22 has a hole 221 that penetrates the center in the axial direction. The hole 221 is connected to the accommodation hole 211 of the body 21. Further, the spacer 22 has a fluid hole 222 and a fluid hole 223 that penetrate in the axial direction on the outer side in the radial direction of the hole 221. The fluid hole portion 222 is connected to an end portion of the injection fluid hole portion 212 formed by the body 21 on the side opposite to the fuel supply portion 25. The fluid hole 223 is connected to the end of the ejection fluid hole 213 formed by the body 21 on the side opposite to the pressure adjustment unit 70. The pipe 23 has a small-diameter hole portion 231 and a large-diameter hole portion 232 that penetrate the central portion in the axial direction. The small diameter hole portion 231 and the large diameter hole portion 232 are provided coaxially. The small diameter hole 231 is connected to the end of the large diameter hole 232 on the spacer 22 side. Further, the pipe 23 has a fluid hole 233 and a fluid hole 234 on the radially outer side of the small diameter hole 231. One end of the fluid hole 233 is connected to the fluid hole 222 formed by the spacer 22, and the other end is connected to the inside of the large-diameter hole 232. The fluid hole 234 has one end connected to the fluid hole 223 formed by the spacer 22 and the other end connected to the inside of the large-diameter hole 232.

  As shown in FIG. 1, the nozzle body 24 has a needle hole 241 that penetrates the central portion in the axial direction. The needle hole 241 has a slightly larger inner diameter than the outer diameter of the needle 30. Therefore, an ejection fluid passage 27 is formed between the inner wall of the nozzle body 24 that forms the needle hole 241 and the outer wall of the needle 30. The jet fluid passage 27 has an end on the pipe 23 side connected to the large-diameter hole 232 of the pipe 23. The nozzle body 24 has a nozzle hole 28 at the tip, that is, the end of the needle hole 241 on the opening side. Further, the nozzle body 24 has a sheet portion 29 on the outer wall at the tip on the radially outer side of the nozzle hole 28.

  Most of the needle 30 is formed in a columnar shape, and has a seal portion 31 at the tip, that is, the end opposite to the body 21. When the seal portion 31 of the needle 30 is in contact with the seat portion 29 of the nozzle body 24, that is, when the seal portion 31 is seated on the seat portion 29, the nozzle hole 28 at the tip of the nozzle body 24 is closed. On the other hand, when the seal portion 31 of the needle 30 is separated from the seat portion 29 of the nozzle body 24, that is, when the seal portion 31 is separated from the seat portion 29, the nozzle hole 28 at the tip of the nozzle body 24 is opened. As shown in FIG. 3, the needle 30 has a small diameter portion 32 at the end opposite to the seal portion 31. The small diameter portion 32 is located in the hole portion 221 of the spacer 22. A cap 33 is attached to the small diameter portion 32. The cap 33 is press-fitted into the small diameter portion 32 and is fixed to the needle 30 by welding or the like.

  A jet fluid chamber 34 is formed between the needle 30 and the large-diameter hole 232 of the pipe 23 as shown in FIG. The ejection fluid chamber 34 is formed between the outer wall of the needle 30, the inner wall of the pipe 23 that forms the large-diameter hole 232, and the end surface 242 on the body 21 side of the nozzle body 24 that is held by the pipe 23. . The ejection fluid chamber 34 has an end on the body 21 side connected to the fluid hole 233 and the fluid hole 234. The ejection fluid chamber 34 is connected to an ejection fluid passage 27 formed between the nozzle body 24 and the needle 30 at the end opposite to the fluid hole 233 and the fluid hole 234. An elastic member 35 is accommodated in the ejection fluid chamber 34. In the case of the present embodiment, the elastic member 35 uses a square spring having a square cross section. One end of the elastic member 35 is in contact with the end surface 242 of the nozzle body 24 on the body 21 side. The other end of the elastic member 35 is locked to the needle 30. The elastic member 35 has a force in the extending direction. Thereby, the elastic member 35 always applies force to the needle 30 in the valve closing direction, that is, the direction in which the seal portion 31 is seated on the seat portion 29.

  The drive unit 40 includes a piezoelectric element 41 in which, for example, piezoelectric elements are stacked. The piezoelectric element 41 is connected to an external ECU (Electronic Control Unit) (not shown) via the wiring part 42 and the terminal part 43. The piezoelectric element 41 expands and contracts due to intermittent energization from an ECU (not shown). The terminal portion 43 of the drive unit 40 is provided at the end of the body 21 opposite to the nozzle hole 28. The driving force transmission unit 50 includes a first piston 51 and a second piston 52. One end of the first piston 51, that is, the end opposite to the injection hole 28 is connected to the piezoelectric element 41 of the drive unit 40. As a result, the first piston 51 reciprocates in the axial direction according to the expansion and contraction of the piezoelectric element 41. The end of the second piston 52 on the first piston 51 side faces the first piston 51 while forming a gap. As shown in FIG. 3, the end of the second piston 52 opposite to the first piston 51 is in contact with the needle 30 with the cap 33 interposed therebetween.

  As shown in FIG. 1, the first piston 51 and the second piston 52 constituting the driving force transmission unit 50 are slidably accommodated in a cylindrical guide member 53. The guide member 53 is fixed to the accommodation hole 211 of the body 21 by, for example, press fitting. The guide member 53 constitutes the housing 20 together with the body 21. As described above, the first piston 51 and the second piston 52 face each other while forming a predetermined gap. A gap formed between the first piston 51 and the second piston 52 accommodated in the guide member 53, that is, a space surrounded by the guide member 53, the first piston 51, and the second piston 52 is a displacement expansion chamber 54. It is. The working fluid is sealed between the body 21 and the driving unit 40 and the driving force transmission unit 50 housed in the housing hole 211. The working fluid is, for example, a liquid fluid that is different from the jet fluid such as silicone oil. The working fluid lubricates between the body 21 and the drive unit 40 and the drive force transmission unit 50 and is introduced into the displacement expansion chamber 54. The working fluid flows into the displacement expansion chamber 54 via the sliding portion between the guide member 53 and the first piston 51 and the second piston 52. Thereby, the driving force of the first piston 51 driven by the driving unit 40 is transmitted to the second piston 52 via the working fluid stored in the displacement expansion chamber 54.

  The sectional area of the second piston 52 is smaller than the sectional area of the first piston 51. Therefore, the displacement of the first piston 51 is transmitted to the second piston 52 via the working fluid in the displacement expansion chamber 54, so that the displacement amount of the second piston 52 is larger than that of the first piston 51. As a result, the movement amount of the second piston 52 relative to the extension amount of the drive unit 40, that is, the movement amount of the needle 30 pushed by the second piston 52 is increased. Further, in the spacer 22, the inner diameter of the spacer 22 forming the hole 221 is slightly larger than the outer diameter of the cap 33 as shown in FIG. 3. Therefore, the working fluid flows from the accommodation hole 211 of the body 21 into the hole 221 of the spacer 22. An elastic member 55 such as a coil spring is provided between the second piston 52 and the guide member 53. The elastic member 55 has a force in the extending direction. Thereby, the second piston 52 is pressed in the direction away from the guide member 53, that is, toward the needle 30 side.

  As shown in FIG. 4, the diaphragm 60 is sandwiched between the spacer 22 and the pipe 23. The diaphragm 60 has a hole 61 at the center. The small diameter portion 32 of the needle 30 passes through the hole 61. The diaphragm 60 has a fluid hole 62 and a fluid hole 63 on the radially outer side of the hole 61. The fluid hole 62 connects the fluid hole 222 of the spacer 22 and the fluid hole 233 of the pipe 23. The fluid hole 63 connects the fluid hole 223 of the spacer 22 and the fluid hole 234 of the pipe 23.

  As shown in FIGS. 1 and 5, the pressure adjusting unit 70 has a piston member 71. The piston member 71 is accommodated in the accommodating chamber 72 of the body 21 so as to be capable of reciprocating in the axial direction. The storage chamber 72 is sealed at its end by a plug 73. By accommodating the piston member 71 in the storage chamber 72, an ejection fluid chamber 74 and a working fluid chamber 75 are formed between the body 21 forming the storage chamber 72 and the piston member 71. The jet fluid chamber 74 is connected to the jet fluid hole 213 via the jet fluid hole 76 that penetrates the body 21. As a result, the jet fluid is introduced into the jet fluid chamber 74. The working fluid chamber 75 is connected to the accommodation hole 211 via a working fluid hole 77 that penetrates the body 21. As a result, the working fluid is introduced into the working fluid chamber 75. As shown in FIG. 5, the piston member 71 has a jet fluid pressure receiving surface 78 at the end on the jet fluid chamber 74 side, and a working fluid pressure receiving surface 79 at the end on the working fluid chamber 75 side. In the case of the first embodiment, the jet fluid pressure receiving surface 78 and the working fluid pressure receiving surface 79 are set to have the same area. Between the body 21 forming the housing chamber 72 and the piston member 71, a seal member 81 is provided that tightly seals between the ejection fluid chamber 74 and the working fluid chamber 75. Thereby, the flow of the fluid between the ejection fluid chamber 74 and the working fluid chamber 75 is interrupted while ensuring the movement of the piston member 71. The ejection fluid chamber 74 accommodates an elastic member 82 such as a coil spring. The working fluid chamber 75 also houses an elastic member 83 such as a coil spring. The elastic member 82 and the elastic member 83 position the piston member 71 in the intermediate portion of the storage chamber 72 that is the initial position when the pressures of the jet fluid and the working fluid are not applied.

  Injected fluid holes 76, 212, 213 of the body 21, fluid holes 222, 223 of the spacer 22, fluid holes 62, 63 of the diaphragm 60, and pipe 23 provided between the fuel supply unit 25 and the nozzle hole 28. The small-diameter hole portion 231, the large-diameter hole portion 232, the fluid hole portions 233 and 234, the jet fluid chamber 34, and the jet fluid passage 27 of the nozzle body 24 constitute the jet fluid supply portion of the claims. Further, the housing hole 211 and the working fluid hole 77 of the body 21 connected to the displacement expansion chamber 54 and the hole 221 of the spacer 22 constitute a working fluid supply part in the claims. The working fluid is enclosed in the accommodation hole 211, the working fluid hole 77, and the hole 221 that constitute the working fluid supply unit sealed by the plug 73.

  The diaphragm 60 is sandwiched between the spacer 22 and the pipe 23 to partition the hole portion 221 of the spacer 22 and the small diameter hole portion 231 of the pipe 23. That is, the diaphragm 60 partitions the small-diameter hole portion 231 of the pipe 23 constituting the jet fluid supply section and the hole portion 221 of the spacer 22 constituting the working fluid supply section. As shown in FIG. 4, a working fluid chamber 91 into which the working fluid flows from the hole 221 of the spacer 22 is formed between the spacer 22 and the diaphragm 60. On the other hand, a jet fluid chamber 92 into which jet fluid flows from the small diameter hole 231 of the pipe 23 is formed between the pipe 23 and the diaphragm 60. As a result, the diaphragm 60 receives force from the jet fluid present in the jet fluid chamber 92 and the working fluid present in the working fluid chamber 91. The area of the diaphragm 60 facing the ejection fluid chamber 92 and the area of the diaphragm 60 facing the working fluid chamber 91 are set to be the same. A stretchable packing 93 is provided between the cap 33 and the diaphragm 60 on the outer peripheral side of the small diameter portion 32 of the needle 30. In the packing 93, one end in the axial direction is in close contact with the lower end of the cap 33, that is, the end on the injection hole 28 side, the other end in the axial direction is in close contact with the upper end of the diaphragm 60, that is, the cap 33 side. 32 is in close contact. Thereby, mixing with the injection fluid of the small diameter hole part 231 of the pipe 23 and the working fluid of the hole part 221 of the spacer 22 is prevented.

Next, the operation of the pressure adjusting unit 70 and the reduction of the deformation of the diaphragm 60 due to this will be described.
The piston member 71 of the pressure adjusting unit 70 is provided between the ejection fluid chamber 74 connected to the ejection fluid supply unit and the working fluid chamber 75 connected to the working fluid supply unit as described above. The piston member 71 is movable in the axial direction on the inside of the body 21 that forms the accommodation chamber 72. Therefore, when the pressure of the jet fluid or the pressure of the working fluid in the working fluid chamber 75 changes in the jet fluid chamber 74, the piston member 71 moves inside the storage chamber 72. As the piston member 71 moves, the pressure of the jet fluid in the jet fluid chamber 74 and the pressure of the working fluid in the working fluid chamber 75 are balanced. For example, when the pressure of the injection fluid decreases due to lack of the injection fluid that is fuel, for example, a force that moves to the injection fluid chamber 74 is applied to the piston member 71. In the piston member 71, the ejection fluid pressure receiving surface 78 facing the ejection fluid chamber 74 and the working fluid pressure receiving surface 79 facing the working fluid chamber 75 have the same area. Therefore, when the pressure of the jet fluid in the jet fluid chamber 74 decreases, the force that the piston member 71 receives from the working fluid in the working fluid chamber 75 becomes larger than the force that the piston member 71 receives from the jet fluid in the jet fluid chamber 74. Thereby, the piston member 71 moves to the jet fluid chamber 74 side, and the volume of the jet fluid chamber 74 decreases. As the volume of the ejection fluid chamber 74 decreases, the pressure of the working fluid sealed in the sealed working fluid supply unit decreases. As a result, the pressure of the ejection fluid in the ejection fluid supply unit connected to the ejection fluid chamber 74 and the pressure of the working fluid in the working fluid supply unit connected to the working fluid chamber 75 are maintained the same.

  Thus, the movement of the piston member 71 of the pressure adjusting unit 70 balances the pressure of the jet fluid and the pressure of the working fluid. Therefore, the diaphragm 60 sandwiched between the pipe 23 forming the jet fluid chamber 92 and the spacer 22 forming the working fluid chamber 91 exists in the working fluid chamber 91 and the force received from the jet fluid existing in the jet fluid chamber 92. The force received from the working fluid is balanced. As a result, the diaphragm 60 is reduced from being deformed toward the spacer 22 or the pipe 23 due to the pressure difference between the jet fluid and the working fluid. Further, the change in pressure generated in the jet fluid or the working fluid is reduced by the movement of the piston member 71 of the pressure adjusting unit 70. Therefore, even if a change in pressure occurs in the jet fluid due to, for example, pressure pulsation, the change is absorbed by the movement of the piston member 71. As a result, the vibration of the diaphragm 60 due to the pressure change of the jet fluid is reduced. Thus, by reducing the deformation and vibration of the diaphragm 60, it is not necessary to increase the plate thickness of the diaphragm 60 in order to ensure the strength and durability of the diaphragm 60. Therefore, the driving force required for the driving unit 40 to drive the diaphragm 60 together with the needle 30 is reduced. As a result, an increase in the size of the drive unit 40 and an increase in power consumption are suppressed.

Next, the operation of the injector 10 configured as described above will be briefly described. When the drive unit 40 is not energized, the total length of the piezoelectric element 41 of the drive unit 40 is the shortest. Therefore, the first piston 51 does not receive a force from the piezoelectric element 41. As a result, the second piston 52 facing the first piston 51 across the displacement expansion chamber 54 and the needle 30 in contact with the second piston 52 do not receive force from the piezoelectric element 41 of the drive unit 40. As a result, the needle 30 is pushed up toward the second piston 52 by the pressing force of the elastic member 35, and the seal portion 31 is seated on the seat portion 29. Therefore, when the drive unit 40 is not energized, the jet fluid is not jetted from the nozzle hole 28.

  When the drive unit 40 is energized, the entire length of the piezoelectric element 41 of the drive unit 40 increases. Therefore, the piezoelectric element 41 drives the first piston 51 to the displacement expansion chamber 54 side. When the first piston 51 moves to the displacement expansion chamber 54 side, the working fluid in the displacement expansion chamber 54 is compressed, and the movement of the first piston 51 moves to the second piston 52 via the working fluid in the displacement expansion chamber 54. Communicated. At this time, since the cross-sectional area of the second piston 52 is smaller than the cross-sectional area of the first piston 51 facing the displacement expansion chamber 54, the movement amount of the first piston 51, that is, the displacement is expanded to the second piston 52. Communicated. When the second piston 52 is moved by the movement of the first piston 51, the second piston 52 presses the cap 33 provided at the end of the needle 30 toward the nozzle body 24. Thereby, the needle 30 integral with the cap 33 moves against the pressing force of the elastic member 35 toward the nozzle body 24, that is, downward in FIG. At this time, the packing 93 sandwiched between the cap 33 and the diaphragm 60 is compressed by the movement of the cap 33 integral with the needle 30. As the needle 30 moves toward the nozzle body 24, the seal portion 31 of the needle 30 is separated from the seat portion 29 of the nozzle body 24. Accordingly, when the drive unit 40 is energized, the jet fluid is jetted from the nozzle hole 28.

  When energization to the drive unit 40 is stopped again, the total length of the piezoelectric element 41 decreases. Therefore, the force for pressing the first piston 51 toward the displacement expansion chamber 54 disappears, and the first piston 51 receives the force from the working fluid in the displacement expansion chamber 54 toward the piezoelectric element 41 side. As a result, the first piston 51 moves toward the piezoelectric element 41 as the piezoelectric element 41 is shortened. As the first piston 51 moves toward the piezoelectric element 41, the pressure of the working fluid in the displacement expansion chamber 54 also decreases, so the force pressing the second piston 52 and the needle 30 also decreases. Therefore, the needle 30 and the second piston 52 are moved again toward the body 21 side, that is, upward in FIG. 1 by the pressing force of the elastic member 35. As a result, the seal portion 31 of the needle 30 is seated again on the seat portion 29 of the nozzle body 24. Therefore, by stopping energization to the drive unit 40, the ejection of the ejection fluid from the nozzle hole 28 is completed.

As described above, by intermittently energizing the drive unit 40, the ejection of the ejected fluid from the nozzle hole 28 is also intermittently performed.
In the first embodiment described above, the balance between the pressure of the ejected fluid in the ejected fluid supply unit and the pressure of the working fluid in the working fluid supply unit is achieved by the movement of the piston member 71 of the pressure adjusting unit 70. Therefore, the pressure of the jet fluid and the pressure of the working fluid are maintained the same. Thereby, the diaphragm 60 which prevents mixing with the injection fluid of an injection fluid supply part and the working fluid of a working fluid supply part reduces the deformation | transformation accompanying the change of the pressure of an injection fluid. Therefore, even if the diaphragm 60 is thinned, strength and durability can be ensured. Moreover, by making the diaphragm 60 thinner, the driving force required for the driving unit 40 can be reduced, and the physique and power consumption of the driving unit 40 can be reduced.

  In the first embodiment, since the jet fluid pressure receiving surface 78 and the working fluid pressure receiving surface 79 of the pressure adjusting unit 70 have the same area, the pressure adjusting unit 70 adjusts the jet fluid and the working fluid to the same pressure. Therefore, the force that the needle 30 receives from the jet fluid side and the force that the needle 30 receives from the working fluid side are balanced. Thereby, both the driving force of the drive part 40 for driving the needle 30 and the pressing force of the elastic member 35 are set small. Therefore, the enlargement of the drive unit 40 and the elastic member 35 can be reduced, and the responsiveness during driving can be improved.

  In the first embodiment, a gas such as hydrogen is used as the jet fluid. By sandwiching the diaphragm 60 between the spacer 22 and the pipe 23, for example, mixing of a gaseous injection fluid such as hydrogen and a liquid working fluid such as silicon oil is prevented. Thereby, it is prevented that the bubble of the injection fluid is contained in the working fluid. Accordingly, it is possible to prevent the malfunction of the working fluid due to the bubbles and the malfunction of the driving unit and the driving force transmission unit due to the malfunction of the working fluid.

(Second Embodiment)
The principal part of the injector by 2nd Embodiment of this invention is shown in FIG.
In the case of 2nd Embodiment, as shown in FIG. 6, the pressure adjustment part 170 is provided with the piston member 171 from which the cross-sectional area of both ends differs. The piston member 171 has a large-diameter portion 181 having a large cross-sectional area and a small-diameter portion 182 having a small cross-sectional area. The housing chamber 172 formed by the body 21 has a large diameter portion 183 and a small diameter portion 184 according to the outer diameter of the piston member 171. The small-diameter portion 184 side of the storage chamber 172 is connected to the jet fluid hole 76 and forms the jet fluid chamber 174 with the piston member 171. The large-diameter portion 183 side of the storage chamber 172 is connected to the working fluid hole 77 and forms a working fluid chamber 175 with the piston member 171. Thereby, the end surface on the small diameter portion 182 side of the piston member 171 forms an ejection fluid pressure receiving surface 178 facing the ejection fluid chamber 174. Further, the end surface on the large diameter portion 181 side of the piston member 171 forms a working fluid pressure receiving surface 179 facing the working fluid chamber 175. The space between the large diameter portion 181 and the large diameter portion 183 is sealed by a seal member 185, and the space between the small diameter portion 182 and the small diameter portion 184 is sealed by a seal member 186.

  In the second embodiment, by providing the piston member 171 with the large diameter portion 181 and the small diameter portion 182, the jet fluid pressure receiving surface 178 and the working fluid pressure receiving surface 179 have different areas. That is, the area of the working fluid pressure receiving surface 179 on the large diameter portion 181 side is larger than that of the jet fluid pressure receiving surface 178 on the small diameter portion 182 side. Thereby, the piston member 171 maintains the pressure of the injection fluid higher than the pressure of the working fluid. That is, the area of the injection fluid pressure receiving surface 178 of the piston member 171 is smaller than the area of the working fluid pressure receiving surface 179. Therefore, when the pressure of the jet fluid is larger than the pressure of the working fluid, the position of the piston member 171 is balanced.

  In the second embodiment, the pressure of the ejection fluid is higher than the pressure of the working fluid. Therefore, the needle 30 receives force in the valve closing direction, that is, the direction in which the seal portion 31 is seated on the seat portion 29 from the jet fluid. That is, the force that the needle 30 receives from the jet fluid in the valve closing direction is larger than the force that the needle 30 receives from the working fluid in the valve opening direction. Thereby, when the energization to the drive unit 40 is stopped and the force applied to the needle 30 from the drive unit disappears, the seal unit 31 is seated on the seat unit 29 by the pressure of the jet fluid. Therefore, the elastic member 35 that applies force to the needle 30 in the valve closing direction becomes unnecessary, and the number of parts can be reduced. Moreover, since the elastic member 35 becomes unnecessary, when the needle 30 moves in the valve opening direction, the force of the elastic member 35 is not applied to the needle 30. Therefore, the driving force of the driving unit 40 is reduced. Therefore, the size of the drive unit 40 can be reduced and the power consumption can be reduced.

(Other embodiments)
In the plurality of embodiments described above, the configuration in which the housing 20 is divided into the body 21, the spacer 22, the pipe 23, and the nozzle body 24 and the diaphragm 60 is sandwiched between the spacer 22 and the pipe 23 has been described. However, the division form of the housing 20 and the position of the diaphragm 60 can be arbitrarily set, and are not limited to the above example.
Moreover, in several embodiment, the structure which accommodates the piston member 71 of the pressure adjustment part 70 in the storage chamber 72 of the body 21 integrally was demonstrated. However, the pressure adjusting unit 70 may be provided separately from the body 21, that is, outside the injector 10. In the plurality of embodiments, the example in which the seal portion 31 of the needle 30 is seated on the seat portion 29 provided on the outer wall of the nozzle body 24 has been described. A seat portion may be provided.

  Further, in the above-described plurality of embodiments, the example in which the piezoelectric element 41 is used as the driving unit 40 has been described. However, the drive unit 40 is not limited to the piezoelectric element 41 such as one that is electromagnetically driven by a coil or the like. The jetting fluid and the working fluid of the injector 10 may be liquids as long as they are different materials, and are not limited to the above examples.

  The present invention described above is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the gist thereof.

Sectional drawing which shows the outline of the injector by 1st Embodiment of this invention Schematic which shows the fuel-injection system to which the injector by 1st Embodiment of this invention is applied. 1 is an enlarged sectional view of the vicinity of the spacer in FIG. 1 is an enlarged sectional view of the vicinity of the diaphragm in FIG. 1 is an enlarged cross-sectional view of the vicinity of the pressure adjustment unit in FIG. Sectional drawing equivalent to FIG. 5 of the injector by 2nd Embodiment of this invention

Explanation of symbols

  In the drawings, 10 is an injector, 20 is a housing, 25 is a fuel supply unit (injection fluid supply unit), 27 is an injection fluid passage (injection fluid supply unit), 28 is an injection hole, 30 is a needle, and 34 is an injection fluid chamber ( (Jetting fluid supply unit), 40 is a driving unit, 50 is a driving force transmitting unit, 54 is a displacement expansion chamber, 60 is a diaphragm (partition member), 70 and 170 are pressure adjusting units, 71 and 171 are piston members, 72 and 172 Is a containing chamber, 74 and 174 are jetting fluid chambers, 75 and 175 are working fluid chambers, 76 is a jetting fluid hole (jetting fluid supply unit), 77 is a working fluid hole (working fluid supply unit), and 78 and 178 are Injecting fluid pressure receiving surface, 79 and 179 are working fluid pressure receiving surfaces, 91 is a working fluid chamber (working fluid supply unit), 92 is a jetting fluid chamber (jetting fluid supply unit), 211 is a receiving hole (working fluid supply unit), 212, 213 are jet fluid holes (Injection fluid supply section), 221 holes (working fluid supply section), 222, 223 fluid holes (jetting fluid supply section), 233 and 234 shows a fluid hole (the injection fluid supply unit).

Claims (6)

A needle for intermittently ejecting the ejection fluid from the nozzle hole;
An injection fluid supply unit for supplying the injection fluid to the injection hole;
A drive unit that transmits displacement due to energization from the opposite end side of the needle to the needle via a working fluid different from the jet fluid filled in a displacement expansion chamber, and drives the needle;
A working fluid supply section in which the working fluid supplied to the displacement expansion chamber is sealed;
A partition member that partitions between the ejection fluid supply unit and the working fluid supply unit in order to regulate mixing of the ejection fluid and the working fluid;
An injection fluid pressure receiving surface that receives the pressure of the injection fluid from the injection fluid supply unit; and a working fluid pressure reception surface that receives the pressure of the working fluid from the working fluid supply unit; A piston member that moves by the difference and adjusts a pressure difference between the jet fluid and the working fluid;
An injector comprising: The jet fluid pressure receiving surface and the working fluid pressure receiving surface have the same area,
The injector according to claim 1, wherein the piston member adjusts the pressure of the jet fluid and the working fluid to be the same. The ejection fluid pressure receiving surface has a smaller area than the working fluid pressure receiving surface,
The injector according to claim 1, wherein the piston member forms a pressure difference between the jet fluid and the working fluid according to an area difference between the jet fluid pressure receiving surface and the working fluid pressure receiving surface. .   4. The injector according to claim 1, wherein the jet fluid is a gas.   The injector according to claim 4, wherein the gas is hydrogen. The ejection fluid supply section and the working fluid supply section are provided, and the needle is accommodated so as to be reciprocally movable in the axial direction, and the partition member and the drive section are disposed on an end portion opposite to the nozzle hole of the needle. Further comprising a housing provided with
The front piston member
Accommodated in a cylindrical accommodation chamber provided integrally with the housing;
Between the housing, the jet fluid pressure receiving surface faces the jet fluid supply unit side, and a jet fluid chamber is formed in which the jet fluid is supplied from the jet fluid supply unit, and the jet fluid supply unit side has the jet fluid chamber. A working fluid pressure receiving surface faces to form a working fluid chamber to which the working fluid is supplied from the working fluid supply unit, and the pressure difference between the jetting fluid in the jetting fluid chamber and the working fluid in the working fluid chamber The injector according to any one of claims 1 to 5, wherein the injector moves in the storage chamber.

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