JP2011012669A - Fuel injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection device which surely performs the high speed displacement of a valve member.SOLUTION: A fuel spray device 100 has, in a pressure control chamber 53 formed in a valve body 40, an inflow-side fuel flow path 52 and an outflow-side fuel flow path 54 which communicate with the pressure control chamber 53, and a floating plate 70 which blocks the inflow-side fuel flow path 52 by the pressure of the fuel where a nozzle needle 60 whose sliding portion 62 is slidably disposed in the minimum diameter portion of the inner circumferential portion 59 of a cylinder 56 is restricted from being displaced to the pressure control chamber 53 by making a step 63 abut on a needle stopper 57 in a position in which a pressure receiving portion 61 is spaced from the floating plate 70, and the cylinder 56 and the nozzle needle 60 in addition forms a space 90 communicating with the needle stopper 57 and the step 63 between the inner circumferential portion 59 and the sliding portion 62.

Description

  In the present invention, the injection from the injection hole of the fuel supplied from the supply source via the supply fuel flow path is controlled by the valve unit according to the control signal from the control device, and supplied from the supply fuel flow path The present invention relates to a fuel injection device in which a part of fuel flows out into a return fuel flow path.

  2. Description of the Related Art Conventionally, a fuel injection device is known that includes a valve body having a valve seat portion, and a valve member having a seat portion that can be reciprocally displaced with respect to the valve body and forms a valve portion together with the valve seat portion. The valve member further includes a pressure receiving portion that receives pressure from the fuel in the pressure control chamber formed in the valve body, and is displaced according to the pressure of the fuel in the pressure control chamber, so that the seat portion is seated on the valve seat portion. It is free. In addition, an inflow side flow path portion and an outflow side flow path portion communicating with the pressure control chamber are further formed in the valve body. The outflow side fuel flow path is provided with a pressure control valve that switches between communication and shutoff according to a control signal from the control device.

  Further, the fuel injection device disclosed in Patent Document 1 further includes a blocking member capable of displacing the control chamber in the pressure control chamber. This shut-off member is a member that is biased toward the inflow side fuel flow path by the pressure of the fuel by switching the outflow side flow path section to the return fuel flow path section by the pressure control valve.

  According to the fuel injection apparatus of Patent Document 1 as described above, when the pressure control valve returns the outflow side fuel flow path and switches to the communication state with the fuel flow path in accordance with the control signal from the control apparatus, The pressure in the control chamber decreases. According to the control of the fuel pressure by the pressure control valve, the shut-off member disposed in the pressure control chamber is urged toward the inflow side fuel flow path side to block communication between the inflow side fuel flow path and the pressure control chamber. . When the pressure in the pressure control chamber rapidly decreases due to the blockage of the fuel inflow from the inflow side fuel flow path, the valve member quickly starts linear reciprocating displacement toward the pressure control chamber side of the valve body. Thus, the seat portion is separated from the valve seat portion.

  On the other hand, the fuel injection device disclosed in Patent Document 2 includes a valve body provided with a cylindrical cylindrical member, and a valve member fitted inside the cylindrical member and reciprocally displaced along the axial direction. . The cylindrical member is formed with a reverse stop shoulder located on the valve seat side of the support portion in the axial direction and located radially outside the smallest diameter portion of the inner peripheral portion of the cylindrical member. Yes. In addition, the valve member includes a columnar sliding portion that is slidably supported on the inner peripheral portion of the cylindrical member, and a reverse stopping shoulder portion of the cylindrical member that faces the valve member in the axial direction. Further, a stop shoulder portion is provided which is positioned on the seat portion side and on the radially outer side of the sliding portion. In the above configuration, the valve member causes the stop shoulder to come into contact with the reverse stop shoulder of the cylindrical member due to the displacement toward the pressure control chamber, so that the displacement toward the pressure control chamber is restricted. It is.

JP-A-6-108948 Japanese Patent No. 4054621

  Now, in the fuel injection device provided with the blocking member as disclosed in Patent Document 1, the linear displacement of the valve member that has started to be displaced toward the control chamber due to the pressure drop in the pressure control chamber is difficult to be regulated. Therefore, the pressure receiving part that receives pressure from the pressure control chamber may come into contact with the blocking member that is displaceable in the pressure control chamber due to the displacement of the valve member. Once the fuel is expelled from between the pressure receiving portion and the shut-off member by this contact, the pressure receiving portion and the shut-off member are adsorbed to each other by the pressure of the fuel in the pressure control chamber and around the valve portion. The blocking member and the valve member, whose movements are regulated by this adsorption, cannot perform different operations. According to such an integral operation of the shutoff member and the valve member, specifically, the valve portion is not correctly opened or closed, or the shutoff member shuts off the pressure control chamber and the inflow side flow passage portion. As a result, the operation to be performed is not performed correctly.

  Thus, as disclosed in Patent Document 2, it is conceivable to provide the valve body and the valve member with a configuration that restricts the displacement of the valve member toward the pressure control chamber. However, in the configuration disclosed in Patent Document 2, the reverse stop shoulder is positioned on the valve seat side of the inner peripheral portion in the axial direction, and the stop shoulder is seated more than the sliding portion in the axial direction. It is located on the part side and radially outside the sliding part. The cylindrical member and the valve member do not substantially form a space between the inner peripheral portion and the sliding portion. Therefore, due to the displacement of the valve member to the pressure control chamber side, the fuel located between the reverse stop shoulder and the stop shoulder is caused by the inner peripheral portion and the slide adjacent to the reverse stop shoulder and the stop shoulder, respectively. Compressed while staying between the reverse stop shoulder and the stop shoulder without being driven away between the parts, showing a rapid pressure rise. Furthermore, when the valve member is displaced to the valve side from the state where the reverse stop shoulder and the stop shoulder are in contact with each other, there is a rapid pressure drop between the reverse stop shoulder and the stop shoulder where it is difficult to supply fuel. Thus, there is a possibility that the stop portion and the reverse stop portion are instantaneously adsorbed. According to the above, when the configuration disclosed in Patent Document 2 is used as it is, a force that hinders the displacement of the valve member is generated due to the pressure fluctuation between the reverse stop shoulder and the stop shoulder. Therefore, the effect of high-speed displacement of the valve member that should be obtained by installing the blocking member is hindered.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a fuel injection device capable of reliably realizing high-speed displacement of a valve member.

  In order to achieve the above object, according to the first aspect of the present invention, the injection from the nozzle hole of the fuel supplied from the supply source via the supply fuel flow path is performed according to the control signal from the control device. In the fuel injection device controlled by the unit and in which a part of the fuel supplied from the supply fuel flow path flows out to the return fuel flow path, the inflow side fuel flow path communicating with the supply fuel flow path side and the radial direction are cylindrical A pressure control chamber that is partitioned by members and into which fuel flows from the inflow side fuel flow path, an outflow side fuel flow path that communicates with the return fuel flow path to allow fuel to flow out of the pressure control chamber, and an outflow side fuel flow of the cylindrical member A first restricting portion that is provided on the opposite side of the road side and located radially outside the smallest diameter portion of the inner peripheral portion of the cylindrical member, and a pressure control chamber and a return fuel flow path according to a control signal By switching between communication and shut-off, the fuel pressure in the pressure control chamber is reduced. The pressure control valve to be controlled is disposed so as to be displaceable in the pressure control chamber, and when the outflow side fuel passage is switched to the return fuel passage, the communication between the inflow side fuel passage and the pressure control chamber is cut off. A blocking member that is biased toward the inflow side fuel flow path by the pressure of the fuel in the pressure control chamber, a pressure receiving portion that partitions the valve portion side of the pressure control chamber and receives the fuel pressure in the pressure control chamber, and an inner circumference A valve that opens and closes the valve portion by reciprocating in the axial direction of the cylindrical member according to the fuel pressure in the pressure control chamber received by the pressure receiving portion. A first regulating member that is opposed to the first regulating part in the axial direction, is located on the valve side of the sliding part and radially outside the sliding part, and the pressure receiving part is separated from the blocking member. A first abutting part that regulates displacement to the pressure control chamber side by abutting on the part. A valve member, and a space formed between the cylindrical member and the valve member, and at least in a closed state of the valve portion, communicated between the first restricting portion and the first contact portion, In addition, when the first restricting portion and the first contact portion are in contact with each other, a cylindrical member and a space partitioned by a valve member are provided.

  According to this invention, the valve member displaced to the pressure control chamber side causes the first abutting portion to abut on the first restricting portion located radially outside the smallest diameter portion of the inner peripheral portion of the cylindrical member. Thereby, the displacement to the pressure control chamber side is regulated at the position where the pressure receiving part is separated from the blocking member. By regulating the displacement of the valve member, the contact between the pressure receiving portion of the valve member that receives the pressure of the fuel in the pressure control chamber and the blocking member that displaces the pressure control chamber is avoided. Can be interposed. Therefore, the valve member and the blocking member can perform different operations without being adsorbed by the pressure of fuel in the pressure control chamber and in the vicinity of the valve portion.

  Further, the first restricting portion is located on the opposite side to the outflow side fuel flow path side of the cylindrical member and on the radially outer side than the minimum diameter portion of the inner peripheral portion. Further, the first abutting portion is opposed to the first restricting portion in the axial direction of the cylindrical member, and is located on the valve portion side with respect to the sliding portion and on the radially outer side of the sliding portion. In addition, a space communicating between the first restricting portion and the first contact portion is formed between the cylindrical member and the valve member when the valve portion is closed. According to the above, since the space defined by the cylindrical member and the valve member is formed when the valve member is displaced toward the pressure control chamber, the space is defined as the first restriction portion and the first contact portion. By communicating in between, the fuel which should be repelled between an inner peripheral part and a sliding part flows into the said space. Therefore, the fluctuation of the pressure increase between the first restricting portion and the first contact portion due to the displacement of the valve member toward the pressure control chamber is reduced. In addition, since the space can exist even when the first abutting portion comes into contact with the first restricting portion, the fluctuation of the pressure increase between the first restricting portion and the first abutting portion can be reduced. It can be carried out until the displacement of the pressure toward the pressure control chamber is completed. Further, the pressure between the first restricting portion and the first abutting portion forms a space because the space between the first restricting portion and the first abutting portion is in contact with the fuel in the space and the fuel supplied from the supply source. Compared with the case where it is not done, it can be distributed at a high pressure as a whole. For this reason, when the valve member is displaced toward the valve portion, the first restricting portion and the first contact portion are difficult to adsorb.

  Further, the space formed between the cylindrical member and the valve member is partitioned by the cylindrical member and the valve member when the first restricting portion and the first contact portion are in contact with each other. Therefore, it can return between the 1st control part and 1st contact part which are connected to the said space by the displacement to the valve part side of a valve member. Thereby, the fluctuation | variation in which the pressure between a 1st control part and a 1st contact part falls is relieve | moderated. As described above, the force that hinders the displacement of the valve member caused by the pressure fluctuation between the first restricting portion and the first contact portion is reduced.

  Therefore, the action of the blocking member is reliably exhibited, and the fuel injection device can reliably realize the high-speed displacement of the valve member.

  According to invention of Claim 2, a valve member comprises the recessed part which forms space between a sliding part and a 1st contact part, and the said recessed part is a depth direction in the radial direction of the sliding part. It is characterized by. According to this invention, the pressure fluctuation due to the displacement of the valve member of the first restricting portion and the first abutting portion is mitigated by the recess located between the sliding portion and the first abutting portion. Moreover, the said recessed part expands the area | region which overlaps with the internal peripheral part of a cylindrical member according to the displacement to the pressure control chamber side of a valve member. Thereby, the space formed between the inner peripheral portion and the sliding portion gradually increases until the first contact portion comes into contact with the first restricting portion. Therefore, the pressure fluctuation due to the displacement of the valve member of the first restricting portion and the first contact portion is reliably mitigated.

  According to a third aspect of the present invention, the concave portion is continuously formed in an annular shape between the sliding portion and the first contact portion in the circumferential direction of the sliding portion. According to the present invention, the space for relaxing the pressure fluctuation is continuously formed in an annular shape in the circumferential direction of the sliding portion. Therefore, the fuel located between the first restricting portion and the first contact portion can smoothly move to the space formed by the recesses in all circumferential directions. As described above, the increase in pressure between the first restricting portion and the first contact portion is more reliably mitigated by the space formed between the cylindrical member and the valve member.

  According to the invention of claim 4, a plurality of recesses are formed between the sliding part and the first abutting part at intervals in the circumferential direction of the sliding part. . According to the present invention, a plurality of spaces for reducing pressure fluctuations are formed between the sliding portion and the first contact portion at intervals in the circumferential direction of the sliding portion. Therefore, the fuel located between the first restriction portion and the first contact portion can smoothly move to any one of the plurality of spaces. As described above, an increase in pressure between the first restricting portion and the first contact portion is reliably mitigated.

  According to the invention described in claim 5, the cylindrical member includes a recess that forms a space between the inner peripheral portion and the first restricting portion, and the concave portion deepens the radial direction of the inner peripheral portion. It is characterized by the vertical direction. According to this invention, the cylindrical member is reliably provided between the sliding portion of the valve member by providing the concave portion that forms a space between the inner peripheral portion and the first restricting portion in the cylindrical member. A space can be formed. Therefore, it is possible to realize a space for reducing fluctuations in pressure with a simple configuration.

  According to the sixth aspect of the present invention, the blocking member that displaces the pressure control chamber in the direction along the reciprocating displacement direction of the valve member is likely to come into contact with the pressure receiving portion of the valve member. Therefore, the effect of avoiding the contact between the blocking member and the pressure receiving portion by the first restricting portion and the first abutting portion is exhibited particularly effectively in the invention described in claim 6.

  According to the seventh aspect of the present invention, the valve member is formed in a columnar shape as a whole, and the first contact portion is provided in a portion facing the first restricting portion in the axial direction in the outer peripheral wall portion of the valve member. It is characterized by that. According to the present invention, the first abutting portion provided at the portion facing the first restricting portion in the axial direction in the outer peripheral wall portion of the valve member formed in a columnar shape as a whole contacts the first restricting portion. By doing so, the displacement of the valve member is regulated. According to the above, it is possible to provide a fuel injection device that can reliably regulate the displacement of the valve member with a simple configuration and reliably realize the high-speed displacement of the valve member.

  According to the invention described in claim 8, the first restricting portion is formed by enlarging the inner diameter of the inner peripheral portion which is the inner peripheral wall of the cylindrical member, and the first contact portion is the outer peripheral wall portion of the valve member. It is formed by enlarging the outer diameter of. According to this invention, since the valve member forms the first contact portion by enlarging the outer diameter of the outer peripheral wall portion, the size of the pressure receiving portion due to the addition of the configuration for regulating the displacement. Does not cause any restrictions. Therefore, it can be set as the valve member which has the pressure receiving part which can receive the fluctuation | variation of the pressure in a pressure control chamber reliably. Therefore, the valve member can maintain a high displacement speed.

  According to the ninth aspect of the present invention, the cylindrical member has the second restricting portion, and the blocking member abuts on the second restricting portion to restrict the displacement toward the valve member side. It has the part. According to this invention, the interruption | blocking member is controlled by the 2nd contact part to contact | abut to the 2nd control part which a cylindrical member has, and the displacement to the valve member side is controlled. By restricting the displacement of the blocking member, contact with the pressure receiving portion can be reliably prevented. Thus, the blocking member and the valve member, which are prevented from mutual adsorption, can reliably perform different operations.

  According to the invention described in claim 10, the blocking member is formed in a disk shape, the second restricting portion is provided on an inner peripheral portion which is an inner peripheral wall of the cylindrical member, and the second contact portion is formed by the blocking member. It is provided in the outer peripheral part of this. According to this invention, the 2nd contact part provided in the outer peripheral part of the interruption | blocking member formed in disk shape is made to contact | abut to the 2nd control part provided in the inner peripheral part which is an internal peripheral wall of a cylindrical member. Thus, the displacement of the blocking member is restricted. According to the above, even if the blocking member has a simple configuration, displacement to the valve member side is restricted, and an operation for blocking the pressure control chamber and the inflow side fuel flow path can be reliably performed. It is.

  According to the invention described in claim 11, the second restricting portion is formed by enlarging the inner diameter of the inner peripheral portion which is the inner peripheral wall of the cylindrical member, and the second contact portion is formed on the valve member side of the blocking member. It is formed in the outer peripheral part of this. According to this invention, since the blocking member forms the second contact portion on the outer peripheral portion on the valve member side, it is necessary to reduce the outer diameter due to the addition of the configuration for regulating the displacement of the blocking member. do not do. Therefore, it is possible to provide a blocking member that reliably receives the pressure of the fuel in the pressure control chamber over a wide area and is more strongly biased toward the inflow side fuel flow path side. As described above, when the shutoff member reliably shuts off the communication between the inflow side fuel flow path and the pressure control chamber, the high-speed displacement of the valve member is further assured.

It is a lineblock diagram of a fuel supply system provided with a fuel injection device by a first embodiment of the present invention. 1 is a longitudinal sectional view of a fuel injection device according to a first embodiment of the present invention. It is the figure which expanded the characteristic part of the fuel-injection apparatus by 1st embodiment of this invention. It is the figure which expanded further the characteristic part of the fuel-injection apparatus by 1st embodiment of this invention. It is a figure which shows the modification of FIG. It is a figure which shows the modification of FIG. It is a figure which shows the modification of FIG. It is a figure explaining the characteristic part of the fuel-injection apparatus by 3rd embodiment of this invention, Comprising: It is the VIII-VIII sectional view taken on the line of FIG. It is a figure which shows another modification of FIG. It is a figure which shows another modification of FIG.

  Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. In addition, the overlapping description is abbreviate | omitted by attaching | subjecting the same code | symbol to the corresponding component in each embodiment.

(First embodiment)
FIG. 1 shows a fuel supply system 10 in which a fuel injection device 100 according to a first embodiment of the present invention is used. The fuel injection device 100 of this embodiment is a so-called direct injection fuel supply system that directly injects fuel into the combustion chamber 22 of the diesel engine 20 that is an internal combustion engine.

  The fuel supply system 10 includes a feed pump 12, a high-pressure fuel pump 13, a common rail 14, an engine control device 17, a fuel injection device 100, and the like.

  The feed pump 12 is an electric pump and is accommodated in the fuel tank 11. The feed pump 12 applies a feed pressure that is higher than the vapor pressure of the fuel to the fuel stored in the fuel tank 11. The feed pump 12 is connected to the high-pressure fuel pump 13 by a fuel pipe 12 a and supplies the high-pressure fuel pump 13 with fuel in a liquid phase state to which a predetermined feed pressure is applied. The fuel pipe 12a is provided with a pressure regulating valve (not shown) to keep the pressure of the fuel supplied to the high pressure fuel pump 13 at a predetermined value.

  The high-pressure fuel pump 13 is attached to a diesel engine and is driven by power from the output shaft of the diesel engine. The high-pressure fuel pump 13 is connected to the common rail 14 by a fuel pipe 13 a, further applies pressure to the fuel supplied by the feed pump 12, and supplies the fuel to the common rail 14. In addition, the high pressure fuel pump 13 has a solenoid valve (not shown) electrically connected to the engine control device 17. The pressure of the fuel supplied from the high-pressure fuel pump 13 to the common rail 14 is optimally controlled by the opening / closing control of the electromagnetic valve by the engine control device 17.

  The common rail 14 is a tubular member made of a metal material such as chromium / molybdenum steel, and has a plurality of branch portions 14a corresponding to the number of cylinders per bank of the diesel engine. Each of the branch portions 14a is connected to the fuel injection device 100 by a fuel pipe that forms a supply fuel flow path 14d. The fuel injection device 100 and the high-pressure fuel pump 13 are connected by a fuel pipe that forms a return fuel flow path 14f. With this configuration, the common rail 14 temporarily stores the fuel supplied in a high pressure state by the high-pressure fuel pump 13 and distributes the fuel to the plurality of fuel injection devices 100 via the supply fuel flow path 14d while maintaining the pressure. In addition, the common rail 14 has a common rail sensor 14b and a pressure regulator 14c at each end. The common rail sensor 14 b is electrically connected to the engine control device 17, detects the fuel pressure and temperature, and outputs the detected fuel pressure and temperature to the engine control device 17. The pressure regulator 14c keeps the fuel pressure in the common rail 14 constant, and depressurizes and discharges excess fuel. The surplus fuel that has passed through the pressure regulator 14 c is returned to the fuel tank 11 through a flow path in the fuel pipe 14 e that connects the common rail 14 and the fuel tank 11.

  The fuel injection device 100 is a device that injects fuel with an increased pressure supplied through the branch portion 14 a of the common rail 14 from the injection hole 44. Specifically, the fuel injection device 100 is configured such that the injection from the injection hole 44 of the fuel supplied from the high-pressure fuel pump 13 via the supply fuel flow path 14d is performed according to a control signal from the engine control device 17. 50. In addition, in this fuel injection device 100, the surplus fuel that is a part of the fuel supplied from the supply fuel flow path 14 d and that has not been injected from the injection hole 44 is added to the fuel injection device 100 and the high-pressure fuel pump 13. Is returned to the high-pressure fuel pump 13. The fuel injection device 100 is inserted into an insertion hole provided in the head member 21 that constitutes a part of the combustion chamber 22 of the diesel engine 20 and is attached. A plurality of fuel injection devices 100 are arranged for each combustion chamber 22 of the diesel engine 20, and fuel is injected directly into the combustion chamber 22, specifically at an injection pressure of about 160 to 220 megapascals (MPa). To do.

  The engine control device 17 includes a microcomputer, and in addition to the above-described common rail sensor 14b, a rotation speed sensor that detects the rotation speed of the diesel engine 20, a throttle sensor that detects the throttle opening, an airflow sensor that detects the intake air intake amount, It is electrically connected to various sensors such as a supercharging pressure sensor that detects the supercharging pressure, a water temperature sensor that detects the cooling water temperature, and an oil temperature sensor that detects the oil temperature of the lubricating oil. Based on information from each of these sensors, the engine control device 17 sends an electrical signal for controlling the opening and closing of the solenoid valve of the high pressure fuel pump 13 and the valve portion 50 of each fuel injection device 100 to the high pressure fuel pump 13. Output to the solenoid valve and each fuel injection device 100.

  Next, the configuration of the fuel injection device 100 will be further described based on FIG.

  The fuel injection device 100 includes a control valve driving unit 30, a valve body 40, a nozzle needle 60, and a floating plate 70. For convenience, the valve portion 50 side (downward in FIG. 2) is the front end side of the fuel injection device 100 and the opposite side (upper side in FIG. 2) is the base end side of the fuel injection device 100.

  The control valve drive unit 30 is accommodated in the valve body 40. The control valve drive unit 30 includes a terminal 32, a solenoid 31, a stator 36, a mover 35, a spring 34, and a valve seat member 33. The terminal 32 is made of a metal material having conductivity, and has one end exposed to the outside from the valve body 40 and the other end connected to the solenoid 31. The solenoid 31 is wound in a spiral shape and receives supply of a pulse current from the engine control device 17 via the terminal 32. The solenoid 31 receives this current supply to generate a magnetic field that circulates along the axial direction. The stator 36 is a cylindrical member made of a magnetic material and magnetizes in a magnetic field generated by the solenoid 31. The mover 35 is a two-stage columnar member made of a magnetic material, and is disposed on the axial front end side of the stator 36. The mover 35 is attracted to the proximal end side by a magnetized stator 36. The spring 34 is a coil spring in which a metal wire is wound in a circular shape, and biases the mover 35 in a direction in which the mover 35 is separated from the stator 36. The valve seat member 33 forms a pressure control valve 80 together with a later-described control valve seat 47a of the valve body 40. The valve seat member 33 is provided on the opposite side of the mover 35 from the stator 36, and can be seated on the control valve seat 47a. When the magnetic field is not formed by the solenoid 31, the valve seat member 33 is seated on the control valve seat portion 47 a by the urging force of the spring 34. When a magnetic field is formed by the solenoid 31, the valve seat member 33 is separated from the control valve seat portion 47a.

  The valve body 40 includes a nozzle body 41, a cylinder 56, a first valve body 46, a second valve body 47, a holder 48, and a retaining nut 49. The valve body 40 has an inflow side fuel flow path 52 communicating with the supply fuel flow path 14 d connected to the high pressure fuel pump 13, the common rail 14 (see FIG. 1), and the like, and a cylinder 56. A pressure control chamber 53 into which fuel flows in and an outflow side fuel channel 54 through which fuel flows out from the pressure control chamber 53 are formed in communication with the return fuel channel 14f. Open ends 52 b and 54 b (see FIG. 3) that open to the pressure control chamber 53 of the inflow side fuel flow path 52 and the outflow side fuel flow path 54 are both located on the base end side with respect to the floating plate 70.

  The nozzle body 41 is a bottomed cylindrical member made of a metal material such as chromium / molybdenum steel, and includes a nozzle needle housing portion 43, a valve seat portion 45, and an injection hole 44. The nozzle needle accommodating portion 43 is a cylindrical hole that is formed along the axial direction of the nozzle body 41 and accommodates the nozzle needle 60. High pressure fuel from the high pressure fuel pump 13 and the common rail 14 is supplied to the nozzle needle housing portion 43. The valve seat portion 45 is formed on the bottom wall on the tip side of the nozzle needle housing portion 43 located on the opposite side of the pressure control chamber 53 of the cylinder 56 in the axial direction of the cylinder 56, Touch freely. The nozzle hole 44 is a minute hole portion that is located further on the distal end side of the valve seat portion 45 and is formed in a plurality radially from the inside to the outside of the nozzle body 41. By passing through the minute nozzle holes 44, the high-pressure fuel is atomized and diffused to be easily mixed with air.

  The cylinder 56 is a cylindrical member made of a metal material, and is disposed in the nozzle needle housing portion 43 so as to be coaxial with the housing portion 43, and is held on the distal end side of the first valve body 46. The cylinder 56 defines a pressure control chamber 53 together with a wall portion on the distal end side of the first valve body 46 on the proximal end side. In addition, a cylinder inner peripheral portion 59 is provided on the inner peripheral wall of the cylinder 56. The cylinder inner peripheral portion 59 is a cylindrical portion that is located on the opposite side of the floating plate 70 in the axial direction of the cylinder 56 of the pressure control chamber 53 and slides the nozzle needle 60 in a reciprocating manner along the axial direction. is there. In addition, the part that causes the nozzle needle 60 to tune is the smallest diameter portion of the inner peripheral portion 59 of the cylinder 56 that has the smallest inner diameter.

  The first valve body 46 and the second valve body 47 are cylindrical members made of a metal material such as chromium / molybdenum steel. The second valve body 47 is held on the tip side of the holder 48 and holds the first valve body 46 on the tip side. The first valve body 46 and the second valve body 47 are provided with a part of the inflow side fuel passage 52 and the outflow side fuel passage 54. In particular, the inflow side fuel flow path 52 and the outflow side fuel flow path 54 formed in the second valve body 47 include an inflow side throttle flow path 52a that is a throttle portion for defining the maximum flow rate of each flow path and the outflow side. A side throttle channel 54a is provided. In addition, a control valve seat portion 47 a that forms a pressure control valve 80 together with the valve seat member 33 of the control valve drive portion 30 is provided on the proximal end side of the second valve body 46 a. The pressure control valve 80 can control the pressure of the fuel in the pressure control chamber 53 by switching communication and blocking between the outflow side fuel passage 54 and the return fuel passage 14f.

  The holder 48 is a cylindrical member made of a metal material such as chrome / molybdenum steel, and has vertical holes 48a and 48b formed along the axial direction, and a socket portion 48c. The vertical hole 48 a is a part of the inflow side fuel flow path 52 and communicates with the inflow side fuel flow path 52 formed in the second valve body 47. The vertical hole 48b accommodates the control valve drive unit 30 on the distal end side. In addition, a socket portion 48c is formed on the base end side of the vertical hole 48b so as to close the open end. One end of the terminal 32 of the control valve drive unit 30 protrudes inside the socket portion 48c, and can be fitted to a plug portion (not shown) connected to the engine control device 17. According to the connection between the socket portion 48c and a plug portion (not shown), it is possible to supply a pulse current from the engine control device 17 to the control valve drive portion 30.

  The retaining nut 49 is a two-stage cylindrical member made of a metal material, and accommodates a part of the nozzle body 41, the first valve body 46, and the second valve body 47, and on the front end side of the holder 48. It is screwed. In addition, the retaining nut 49 forms a stepped portion 49a at the inner peripheral wall portion. The step 49a urges the nozzle body 41 and the first and second valve bodies 46a and 46b toward the holder 48 by attaching the retaining nut 49 to the holder 48.

  The nozzle needle 60 is formed in a cylindrical shape as a whole by a metal material such as high-speed tool steel, and has a sheet portion 65, a pressure receiving portion 61, a sliding portion 62, and a flange member 67. The seat portion 65 is formed at the tip of the nozzle needle 60 and can be seated on the valve seat 45 of the valve body 40. This seat portion 65 constitutes a valve portion 50 together with the valve seat portion 45 for switching communication and blocking of the high-pressure fuel supplied into the nozzle needle housing portion 43 to the injection hole 44. The pressure receiving portion 61 is formed at the base end portion of the nozzle needle 60, partitions the valve portion 50 side of the pressure control chamber 53, and receives the fuel pressure in the pressure control chamber 53. The sliding portion 62 is a cylindrical portion that is located on the pressure receiving portion 61 side of the nozzle needle 60 and is slidably disposed with respect to the minimum diameter portion of the inner peripheral portion 59 of the cylinder 56. The flange member 67 is an annular member that is fitted on the outer peripheral wall portion of the nozzle needle 60 and is held by the nozzle needle 60.

  In addition, the nozzle needle 60 is urged toward the valve portion 50 by a return spring 66. The return spring 66 is a coil spring in which a metal wire is wound in a circular shape, and the distal end side is a proximal end surface of the flange member 67 and the proximal end side is a distal end surface of the cylinder 56, respectively. I'm seated. The nozzle needle 60 configured as described above is reciprocally displaced linearly in the axial direction of the sliding portion 62 with respect to the cylinder 56 in accordance with the pressure of the fuel in the pressure control chamber 53 received by the pressure receiving portion 61. 65 is seated and separated from the valve seat portion 45, and the valve portion 50 is opened and closed.

  The floating plate 70 is a disk-shaped member made of a metal material and has a throttle channel 71. The floating plate 70 is accommodated in the pressure control chamber 53 inside the cylinder 56 with the axial direction thereof set in the same direction as the axial direction of the cylinder 56, and the reciprocating displacement of the nozzle needle 60. It can be displaced in a direction along the direction. The floating plate 70 controls the pressure so that the communication between the inflow side fuel flow path 52 and the pressure control chamber 53 is cut off when the outflow side fuel flow path 54 and the return fuel flow path 14f are switched to the communication state. It is biased toward the flow path 54 by the pressure of the fuel in the chamber 53. In addition, the throttle channel 71 is formed along the axial direction at the radial center of the floating plate 70. When the inflow side fuel passage 52 is closed by the floating plate 70, the fuel in the pressure control chamber 53 passes through the throttle passage 71 and flows out to the outflow side fuel passage 54. In addition, the flow path area of the throttle flow path 71 is smaller than the flow path area of the outflow side throttle flow path 54a.

(Characteristic part)
Next, the characteristic part of the fuel injection device 100 will be described in more detail with reference to FIGS.

  The valve body 40 further includes a needle stopper 57 and a plate stopper 58. Specifically, the needle stopper 57 and the plate stopper 58 are provided on the inner peripheral portion 59 of the cylinder 56. The needle stopper 57 is located in the cylinder 56 on the valve seat 45 side of the inner peripheral portion 59, and is provided on the opposite side of the cylinder 56 from the outflow side fuel flow channel 54 side. It is located on the tip side of the inner peripheral portion 59 in the axial direction. The needle stopper 57 is formed by enlarging the inner diameter of the inner peripheral portion 59 of the cylinder 56, and is located on the outer side in the radial direction from the inner peripheral surface of the smallest diameter portion which is the adjacent smallest inner diameter portion. ing. The plate stopper 58 is located on the proximal end side of the inner peripheral portion 59 in the cylinder 56 and is formed by expanding the inner diameter of the inner peripheral portion 59.

  The nozzle needle 60 further has a stepped portion 63 on the outer peripheral wall portion. The stepped portion 63 is formed by enlarging the outer diameter of the outer peripheral wall portion of the nozzle needle 60, and is located on the seat portion 65 side of the sliding portion 62 and on the radially outer side of the sliding portion 62. ing. The stepped portion 63 is positioned on the distal end side of the needle stopper 57 so as to face the needle stopper 57 in the axial direction. According to the displacement of the nozzle needle 60 toward the pressure control chamber 53, the stepped portion 63 approaches the needle stopper 57 and contacts the needle stopper 57 at a position where the pressure receiving portion 61 is separated from the floating plate 70. It becomes. According to the contact between the stepped portion 63 and the needle stopper 57 as described above, the displacement of the nozzle needle 60 toward the pressure control chamber 53 is restricted.

  In addition, the nozzle needle 60 includes a recess 62 a that forms a space 90 between the sliding portion 62 and the stepped portion 63. The recess 62 a has a radial direction of the sliding portion 62 as a depth direction, and is continuously formed in an annular shape in the circumferential direction of the sliding portion 62. By forming the concave portion 62a, the outer diameter of the outer peripheral wall portion forming the sliding portion 62 of the nozzle needle 60 is changed from the portion directly contacting the inner peripheral portion 59 (FIG. 4Φ A1) to the stepped portion. It is once narrowed toward 63 (FIG. 4Φ B1). In addition, the concave portion 62a overlaps the base end side with the inner peripheral portion 59 in the radial direction even when the valve portion 50 is closed.

  With the above configuration, the cylinder 56 and the nozzle needle 60 form a space 90 that communicates between the needle stopper 57 and the stepped portion 63 between the cylinder 56 and the nozzle needle 60. The space 90 communicates between the needle stopper 57 and the stepped portion 63 at least when the valve portion 50 is closed. The space 90 is partitioned by the cylinder 56 and the nozzle needle 60 when the needle stopper 57 and the stepped portion 63 are in contact with each other. With the above configuration, the space 90 can reduce fluctuations in pressure increase between the needle stopper 57 and the stepped portion 63 when the nozzle needle 60 is displaced toward the pressure control chamber 53.

  In addition, since the recess 62a is formed in the sliding portion 62, the volume of the space 90 increases in accordance with the displacement of the nozzle needle 60 toward the pressure control chamber 53 side. Therefore, the volume of the space 90 is larger when the valve unit 50 is opened and when the valve unit 50 is opened (see the two-dot chain line in FIG. 4). Further, when the valve is closed, the space 90 has an effect of relieving a sudden pressure drop between the needle stopper 57 and the stepped portion 63 contrary to when the valve is opened, and the concave portion 62a overlapping the inner peripheral portion 59 in the radial direction. Thus, the space 90 is already formed at the start of displacement of the nozzle needle 60 toward the pressure control chamber 53. Therefore, the pressure relieving action by the space 90 can be exerted immediately after the start of displacement of the nozzle needle 60.

  The floating plate 70 further has a contact portion 73 that abuts against and contacts the plate stopper 58. Specifically, in the floating plate 70, a radially outer edge portion of the outer peripheral wall portion on the nozzle needle 60 side is used as a contact portion 73. The abutting portion 73 is located on the base end side of the plate stopper 58 so as to face the stopper 58, and approaches and abuts the plate stopper 58 due to the displacement of the floating plate 70 toward the nozzle needle 60 side. . According to the contact between the contact portion 73 and the plate stopper 58 as described above, the displacement of the floating plate 70 toward the nozzle needle 60 is restricted.

  Here, the gap between the pressure receiving portion 61 of the nozzle needle 60 that closes the valve portion 50 and the floating plate 70 that is in contact with the first valve body 46 is the gap between the contact portion 73 and the plate stopper 58. And it is set wider than the total sum of the gaps between the stepped portion 63 and the needle stopper 57. According to the setting of the gap as described above, the displacement of the nozzle needle 60 toward the pressure control chamber 53 is restricted at a position where the pressure receiving portion 61 is separated from the floating plate 70.

  In addition, a plate spring 76 is provided between the nozzle needle 60 and the floating plate 70. The plate spring 76 is a coil spring in which, for example, a metal wire is wound around, and the distal end side is a base end side surface of the nozzle needle 60 and the proximal end side is a distal end side end surface of the floating plate 70. , Each seated. The plate spring 76 biases the floating plate 70 toward the proximal end side with respect to the nozzle needle 60. According to the bias of the plate spring 76, the floating plate 70 is biased toward the inflow side fuel flow path 52 even when there is no pressure difference between the base end side and the tip end side of the plate 70. The first valve body 46 is in contact with the wall portion on the distal end side.

  Further, the opening ends 52 b and 54 b of the inflow side fuel passage 52 and the outflow side fuel passage 54 formed in the first valve body 46 and the second valve body 47 to the pressure control chamber 53 are formed on the floating plate 70. It is arranged so as to be axisymmetric with respect to the central axis. Specifically, the opening end 54 b of the outflow side fuel flow path 54 opens toward the center of the floating plate 70 and faces the throttle flow path 71. In addition, a plurality of opening ends 52 b of the inflow side fuel passage 52 are opened around the opening end 54 b of the outflow side fuel passage 54. According to the arrangement of the opening ends 52 b and 54 b, the axial direction of the floating plate 70 is not easily inclined with respect to the axial direction of the cylinder 56. Thus, the displacement of the floating plate 70 is regulated by causing the contact portion 73 to contact the plate stopper 58 with certainty.

  An operation in which the fuel injection device 100 having the above-described configuration performs fuel injection by opening and closing the valve unit 50 in response to a control signal from the engine control device 17 will be described with reference to FIGS.

  A magnetic field generated by the solenoid 31 according to the pulse current of the engine control device 17 opens the pressure control valve 80. Thus, in the pressure control chamber 53, the fuel outflow from the outflow side fuel passage 54 in communication with the return fuel passage 14f first depressurizes the vicinity of the open end 54b of the outflow side fuel passage 54. The floating plate 70 that is biased toward the inflow side fuel flow path 52 by the biasing force of the plate spring 76 and is in contact with the wall portion on the distal end side of the first valve body 46 is between the proximal end side and the distal end side. Is sucked to the open end 54b side of the outflow side fuel flow path 54, and is urged more strongly to the inflow side fuel flow path 52 side. The inflow side fuel flow path 52 having the opening end 52 b on the same side as the outflow side fuel flow path 54 with respect to the floating plate 70 is blocked from communicating with the pressure control chamber 53 by the biased plate 70. In the pressure control chamber 53 in which the inflow of fuel from the inflow side fuel flow path 52 is blocked, rapid pressure reduction occurs due to the outflow of fuel passing through the throttle flow path 71.

  The sheet mainly from the fuel in the nozzle needle housing portion 43 rather than the sum of the force received by the pressure receiving portion 61 from the fuel in the pressure control chamber 53 and the urging force of the return spring 66 due to the rapid pressure reduction in the pressure control chamber 53. The nozzle needle 60 that has exceeded the force received by the portion 65 and the like is immediately pushed up to the pressure control chamber 53 side at a high speed. The nozzle needle 60 displacing to the pressure control chamber 53 side causes the seat portion 65 to be separated from the valve seat portion 45 and opens the valve portion 50.

  When the nozzle needle 60 is displaced toward the pressure control chamber 53, a space 90 defined by the cylinder 56 and the nozzle needle 60 is formed, and the space 90 communicates between the needle stopper 57 and the stepped portion 63. Yes. Therefore, the fuel that should be repelled between the inner peripheral portion 59 and the sliding portion 62 located between the needle stopper 57 and the stepped portion 63 is the inner periphery adjacent to each of the needle stopper 57 and the stepped portion 63. It flows into the space 90 between the part 59 and the sliding part 62. In this way, by forming the space 90 between the cylinder 56 and the nozzle needle 60, fluctuations in pressure increase between the needle stopper 57 and the stepped portion 63 are alleviated. Further, the nozzle needle 60 that continues to be displaced toward the pressure control chamber 53 side is brought into contact with the floating plate 70 of the pressure receiving portion 61 by bringing the stepped portion 63 into contact with the needle stopper 57. The displacement is restricted. In addition, since the space 90 can exist even when the needle stopper 57 and the stepped portion 63 are in contact with each other, the variation in the pressure increase between the needle stopper 57 and the stepped portion 63 can be reduced. This can be carried out until the displacement toward the pressure control chamber 53 ends.

  The pressure control valve 80 is closed by the disappearance of the magnetic field by the solenoid 31 corresponding to the pulse current of the engine control device 17. As a result, the outflow of fuel from the outflow side fuel passage 54 that has been cut off from the return fuel passage 14f stops. When the fuel flows into the vicinity of the open end 54b of the outflow side fuel flow path 54 through the throttle flow path 71, the urging force of the floating plate 70 toward the open end 54b is finally the plate spring 76. It becomes only the urging force by. Then, the floating plate 70 is pushed down to the nozzle needle 60 side by the pressure of the fuel near the opening end 52 b of the inflow side fuel flow path 52. The floating plate 70, which is displaced toward the nozzle needle 60, has its displacement restricted before contacting the pressure receiving portion 61 of the nozzle needle 60 by bringing the contact portion 73 into contact with the plate stopper 58.

  According to the displacement of the floating plate 70 toward the nozzle needle 60 side, the inflow side fuel flow path 52 and the pressure control chamber 53 communicate with each other again. In the pressure control chamber 53 where the inflow of fuel from the inflow side fuel flow path 52 has been resumed, rapid pressure increase occurs. The sum of the force received by the pressure receiving portion 61 from the fuel in the pressure control chamber 53 and the urging force by the return spring 66 due to the rapid pressure increase in the pressure control chamber 53 is mainly from the fuel in the nozzle needle housing portion 43. It exceeds the force received by the part 65 and the like again. Then, the nozzle needle 60 is immediately pushed down toward the pressure control valve 80 at a high speed. At this time, the pressure between the needle stopper 57 and the stepped portion 63 is such that the space between the needle stopper 57 and the stepped portion 63 is in contact with the fuel in the space 90 and the fuel supplied from the supply fuel flow path 14d. Compared with the case where no is formed, it can be distributed at a high pressure as a whole. Therefore, when the nozzle needle 60 is displaced toward the valve portion 50 side, the needle stopper 57 and the stepped portion 63 are difficult to adsorb.

  In addition, the space 90 formed between the cylinder 56 and the nozzle needle 60 is partitioned by the cylinder 56 and the nozzle needle 60 when the needle stopper 57 and the stepped portion 63 are in contact with each other. . Therefore, the fuel located in the space 90 can return between the needle stopper 57 and the stepped portion 63 communicating with the space 90 due to the displacement of the nozzle needle 60 toward the valve portion 50. Therefore, the fluctuation of the pressure drop between the needle stopper 57 and the stepped portion 63 is alleviated. And the nozzle needle 60 makes the valve part 50 a valve closing state by seating the seat part 65 on the valve seat part 45.

  In the first embodiment described so far, the contact between the pressure receiving portion 61 and the floating plate 70 can be avoided by restricting the displacement of the nozzle needle 60. Therefore, since the fuel can always be interposed between them, the nozzle needle 60 and the floating plate 70 are not adsorbed by the pressure of the fuel in the pressure control chamber 53 and the nozzle needle housing portion 43. According to the synergistic action of the stepped portion 63 and the needle stopper 57, the nozzle needle 60 and the floating plate 70 can reliably perform different operations as described above.

  Furthermore, by forming a space 90 that can communicate with the needle stopper 57 and the stepped portion 63 between the cylinder 56 and the nozzle needle 60, the fluctuation in pressure between the needle stopper 57 and the stepped portion 63 can be reduced. Therefore, the force which prevents the high-speed displacement of the nozzle needle 60 resulting from the fluctuation | variation of the pressure between the needle stopper 57 and the stepped part 63 can be reduced.

  Therefore, the action of the floating plate 70 is reliably exhibited, and the fuel injection device 100 can surely realize the high-speed displacement of the nozzle needle 60.

  In addition, in the first embodiment, the recess 62a located between the sliding portion 62 and the stepped portion 63 overlaps with the inner peripheral portion 59 according to the displacement of the nozzle needle 60 toward the pressure control chamber 53 side. Enlarge the area. With this configuration, the space 90 is increased in accordance with the displacement of the nozzle needle 60 toward the pressure control chamber 53. Therefore, the fuel located between the needle stopper 57 and the stepped portion 63 is in the space formed by the recess 62a. 90 can move smoothly. Therefore, the increase in pressure between the needle stopper 57 and the stepped portion 63 is reliably mitigated by the space 90. And the improvement of this effect is realizable with a simple structure.

  Furthermore, in the first embodiment, the recess 62 a is continuously formed in an annular shape in the circumferential direction of the sliding portion 62, so that the space 90 for reducing the pressure fluctuation is continuous in the circumferential direction of the sliding portion 62. It will be formed in an annular shape. Therefore, the fuel located between the needle stopper 57 and the stepped portion 63 can smoothly move to the space 90 between the sliding portion 62 and the inner peripheral portion 59 in all circumferential directions. As described above, the increase in pressure between the needle stopper 57 and the stepped portion 63 is more reliably mitigated by the space 90 between the inner peripheral portion 59 and the sliding portion 62.

  In the first embodiment, the stepped portion 63 provided on the outer peripheral wall portion of the nozzle needle 60 is brought into contact with the needle stopper 57 provided on the inner peripheral portion 59 of the cylinder 56, so that the configuration is simple. The positive displacement regulation of the nozzle needle 60 is realized. Furthermore, when the stepped portion 63 is formed by increasing the outer diameter of the outer peripheral wall portion of the nozzle needle 60, the size of the pressure receiving portion 61 is not limited due to the addition of the configuration for restricting the displacement. . Therefore, the nozzle needle 60 can reliably receive the pressure fluctuation in the pressure control chamber 53 by the pressure receiving portion 61. Therefore, the nozzle needle 60 can maintain a high displacement speed.

  In addition, in the first embodiment, the plate 70 and the nozzle needle 60 can be prevented from adsorbing each other even when the displacement of the floating plate 70 is restricted by the synergistic action of the contact portion 73 and the plate stopper 58. It becomes. Therefore, the floating plate 70 and the nozzle needle 60 can reliably perform different operations.

  In addition, in the first embodiment, the contact portion 73 is the outer peripheral wall portion of the floating plate 70, and the plate stopper 58 is provided on the inner peripheral portion 59 of the cylinder 56. Therefore, reliable displacement regulation of the floating plate 70 is realized with a simple configuration. In addition, since the contact portion 73 is formed on the outer peripheral wall portion of the floating plate 70 on the nozzle needle 60 side, the plate 70 does not require a reduction in outer diameter due to the addition of a configuration for restricting displacement. . Therefore, the floating plate 70 that reliably receives the pressure of the fuel in the pressure control chamber 53 over a wide area and is more strongly biased toward the inflow side fuel flow path 52 can be obtained.

  The action of avoiding contact between the floating plate 70 and the pressure receiving portion 61 by the needle stopper 57 and the stepped portion 63 is that the displacement direction of the nozzle needle 60 and the floating plate 70 is the same. This is particularly effective in the first embodiment in which contact with the plate 70 is likely to occur.

  In the first embodiment, the engine control device 17 is in the “control device” described in the claims, the high-pressure fuel pump 13 is in the “supply source” in the claims, and the nozzle needle 60 is in the claims. In the “valve member”, the stepped portion 63 is in the “first contact portion” described in the claims, the floating plate 70 is in the “blocking member” in the claims, and the contact portion 73 is in the claims. The cylinder 56 is in the “cylindrical member” described in the claims, the needle stopper 57 is in the “first regulating portion” in the claims, and the plate stopper 58 is in the claims. A part of the inner peripheral portion 59 corresponds to the “second regulating portion” and corresponds to the “minimum diameter portion” recited in the claims.

(Second embodiment)
As shown in FIGS. 5 and 6, the second embodiment of the present invention is a modification of the first embodiment. The floating plate 270, the nozzle needle 260, and the valve body 246 of the second embodiment correspond to the floating plate 70, the nozzle needle 60, the first valve body 46, and the second valve body 47 of the first embodiment, respectively. Hereinafter, the configuration of the second embodiment will be described in detail.

  The floating plate 270 of the second embodiment is not biased to the proximal end side by the plate spring 76 like the floating plate 70 of the first embodiment. In addition, the floating plate 270 has a groove portion 278 provided along the radial direction of the floating plate 270 at an outer edge portion in the radial direction of the outer peripheral wall portion on the nozzle needle 260 side. The groove portion 278 serves as a fuel flow path that connects the base end side and the tip end side of the floating plate 270 in a state where the contact portion 73 of the floating plate 270 and the plate stopper 58 of the cylinder 56 are in contact.

  In addition, in the second embodiment, the flow path shapes of the inflow side fuel flow path 252 and the outflow side fuel flow path 254 communicating with the pressure control chamber 53 are simplified. Corresponding to the simplification of the fuel flow paths 252 and 254, the configuration corresponding to the first valve body 46 and the second valve body 47 in the first embodiment is changed to a single valve body 246 in the second embodiment. It has been simplified. Specifically, the opening end 252b of the inflow side fuel flow path 252 to the pressure control chamber 53 and the opening end 254b of the outflow side fuel flow path 254 to the pressure control chamber 53 are adjacent to each other, and the floating plate 270 Each is opened toward a position eccentric from the center.

  Further, the nozzle needle 260 of the second embodiment is equivalent to the pressure receiving portion 61, the sliding portion 62, and the stepped portion 63 of the nozzle needle 60 according to the first embodiment, and the pressure receiving portion 261, the sliding portion 262, and the stepped portion. H.263. Further, the sliding portion 262 corresponds to the concave portion 62 a of the first embodiment, and includes a concave portion 262 a that is continuously formed in an annular shape in the circumferential direction of the sliding portion 262. By forming the concave portion 262a, the outer diameter of the outer peripheral wall portion that forms the sliding portion 262 of the nozzle needle 260 is changed from the portion that directly contacts the inner peripheral portion 59 (FIG. 6 ΦA2) to the stepped portion. It is once thinner toward H.263 (FIG. 6, ΦB2).

  With the above configuration, the cylinder 56 and the nozzle needle 260 form a space 290 that communicates with the needle stopper 57 and the stepped portion 263 between the inner peripheral portion 59 and the sliding portion 262. When the nozzle needle 260 is displaced toward the pressure control chamber 53, the space 290 can mitigate fluctuations in pressure increase between the needle stopper 57 and the stepped portion 263.

  In addition, since the concave portion 262a is formed in the sliding portion 262, the volume of the space 290 increases in accordance with the displacement of the nozzle needle 260 toward the pressure control chamber 53 side. Therefore, the volume of the space 290 is larger when the valve section 50 (see FIG. 1) is closed and when the valve is opened (see the two-dot chain line in FIG. 6). Furthermore, the space 290 is already formed at the start of displacement of the nozzle needle 260 toward the pressure control chamber 53 due to the form of the concave portion 262a that overlaps with the inner peripheral portion 59 in the radial direction when the valve is closed. Therefore, the pressure relieving action by the space 290 can be exhibited immediately after the start of displacement of the nozzle needle 260.

  In the second embodiment having the configuration described above, the floating plate 270 is separated from the inner wall portion of the valve body 246 in a state where the outflow side fuel flow path 254 is blocked. When the outflow side fuel flow path 254 and the return fuel flow path 14f are switched from this state to the communication state, the floating plate 270 moves toward the open end 254b due to the pressure reduction in the vicinity of the open end 254b of the outflow side fuel flow path 254. It is sucked and displaced. The floating plate 270 comes into contact with the inner wall portion of the pressure control chamber 53 and is strongly urged to block communication between the inflow side fuel flow path 252 and the pressure control chamber 53. From the pressure control chamber 53 in which the inflow of fuel is blocked, the fuel flows out through the throttle channel 71 and the open end 254 b facing the throttle channel 71.

  According to the above, rapid pressure reduction occurs in the pressure control chamber 53, and the nozzle needle 260 is pushed up at a high speed. When the nozzle needle 260 is displaced to the pressure control chamber 53 side, the fuel located between the needle stopper 57 and the stepped portion 263 is moved to the inner peripheral portion 59 and the slide adjacent to the needle stopper 57 and the stepped portion 263, respectively. Driven between the moving parts 262. Therefore, by forming a space 290 that can communicate with the needle stopper 57 and the stepped portion 263 between the cylinder 56 and the nozzle needle 260, fluctuations in pressure increase between the needle stopper 57 and the stepped portion 263 can be reduced. . The displacement of the nozzle needle 260 is restricted by causing the stepped portion 263 to contact the needle stopper 57 before the pressure receiving portion 261 contacts the floating plate 270.

  Further, according to the disconnection between the outflow side fuel flow path 254 and the return fuel flow path 14f, the pressure recovery in the vicinity of the open end 254b of the outflow side fuel flow path 254 and the vicinity of the open end 252b of the inflow side fuel flow path 252 are achieved. The floating plate 270 is pushed down toward the nozzle needle 260 by the high pressure. The displacement of the floating plate 270 is restricted by bringing the contact portion 73 into contact with the plate stopper 58. In addition, according to the operation of the groove portion 278 as a fuel flow path, even when the plate stopper 58 restricts the displacement of the floating plate 270, the inflow of fuel toward the nozzle needle 260 side of the floating plate 270 is prevented. Hard to be disturbed. Therefore, the nozzle needle 260 can be reliably pushed down toward the pressure control valve 80 at a high speed.

  At this time, the fuel located in the space 290 can return between the needle stopper 57 and the stepped portion 263 due to the displacement of the nozzle needle 260 toward the valve portion 50. Therefore, the fluctuation | variation in which the pressure between the needle stopper 57 and the step part 263 falls is relieved. And the nozzle needle 260 makes the valve part 50 a valve closing state by seating the seat part 65 on the valve seat part 45 (refer FIG. 2).

  As described above, the synergistic effect of the stepped portion 263 and the needle stopper 57 is reliably exhibited regardless of the presence or absence of the plate spring 76 and the flow path shapes of the inflow side fuel flow path 252 and the outflow side fuel flow path 254. . In addition, the synergistic action of the contact portion 73 and the plate stopper 58 is also exhibited. Further, the space 290 also reliably reduces the fluctuation in pressure between the needle stopper 57 and the stepped portion 263. Therefore, also in the second embodiment, the high-speed displacement of the nozzle needle 260 is reliably realized.

  In the second embodiment, the nozzle needle 260 is described in the “valve member” described in the claims, the stepped portion 263 is described in the “first contact portion”, and the floating plate 270 is described in the claims. Respectively corresponding to the “blocking member”.

(Third embodiment)
As shown in FIGS. 7 and 8, the third embodiment of the present invention is a modification of the second embodiment. The fuel injection device 300 according to the third embodiment includes a cylinder 356 and a nozzle needle 360 corresponding to the cylinder 56 and the nozzle needle 260 of the second embodiment. Hereinafter, the configuration of the fuel injection device 300 according to the third embodiment will be described in detail.

  The cylinder 356 of the third embodiment has an inner peripheral portion 359 and a needle stopper 357 corresponding to the inner peripheral portion 59 and the needle stopper 57 of the cylinder 56 according to the second embodiment.

  Further, the nozzle needle 360 of the third embodiment has a sliding part 362 and a stepped part 363 corresponding to the sliding part 262 and the stepped part 263 of the nozzle needle 260 according to the second embodiment. The sliding portion 362 includes a plurality of slit portions 362 a at the end on the tip side adjacent to the stepped portion 363. The slit portion 362 a is a recess formed along the axial direction of the nozzle needle 360 with the radial direction of the sliding portion 362 as a depth direction, and has a predetermined interval in the circumferential direction of the sliding portion 362. A plurality of gaps are formed. The plurality of slit portions 362a are formed over the entire circumference at equal intervals in the circumferential direction of the sliding portion 362 (see FIG. 8). In addition, the base end side of each slit portion 362a overlaps with the inner peripheral portion 359 of the cylinder 356 in the radial direction in a state where the valve portion 50 (see FIG. 2) is closed.

  With the above configuration, the cylinder 356 and the nozzle needle 360 form a space 390 communicating with the needle stopper 357 and the stepped portion 363 between the inner peripheral portion 359 and the sliding portion 362. When the nozzle needle 360 is displaced toward the pressure control chamber 53, the space 390 can mitigate fluctuations in pressure increase between the needle stopper 357 and the stepped portion 363.

  In addition, since the slit portion 362 a is formed in the sliding portion 362, the volume of the space 390 increases with the displacement of the nozzle needle 360 toward the pressure control chamber 53. Therefore, the volume of the space 390 is larger when the valve unit 50 is opened and when the valve unit 50 is opened. Furthermore, the space 390 is already formed at the start of displacement of the nozzle needle 360 toward the pressure control chamber 53 due to the form of the slit portion 362a that overlaps with the inner peripheral portion 359 in the radial direction when the valve is closed. Therefore, the pressure relieving action by the space 390 can be exhibited immediately after the start of displacement of the nozzle needle 360.

  In the third embodiment described so far, when the nozzle needle 360 is displaced to the pressure control chamber 53 side, the fuel located between the needle stopper 357 and the stepped portion 363 is the inner peripheral portion 359 adjacent to each of them. And driven between the sliding parts 362. By forming the space 390 between the inner peripheral portion 359 and the sliding portion 362, fluctuations in pressure increase between the needle stopper 357 and the stepped portion 363 can be reduced. On the other hand, according to the displacement of the nozzle needle 360 toward the valve portion 50, the fuel located in the space 390 between the inner peripheral portion 359 and the sliding portion 362 returns between the needle stopper 357 and the stepped portion 363. obtain. Therefore, the fluctuation of the pressure drop between the needle stopper 357 and the stepped portion 363 is alleviated.

  Furthermore, in the third embodiment, a space 390 that reduces pressure fluctuations is provided at a predetermined interval in the circumferential direction of the sliding portion 362 by a plurality of slit portions 362 a formed in the circumferential direction of the sliding portion 362. A plurality of them will be formed. Therefore, the fuel located between the needle stopper 357 and the stepped portion 363 can smoothly move to any one of the plurality of spaces 390 in all circumferential directions. As described above, the increase in pressure between the needle stopper 357 and the stepped portion 363 is more reliably mitigated by the space 390 between the inner peripheral portion 359 and the sliding portion 362.

  The plurality of spaces 390 gradually increase according to the displacement of the nozzle needle 360 toward the pressure control chamber 53 side. Therefore, the fuel located between the needle stopper 357 and the stepped portion 363 can move to the space 390 more smoothly. Therefore, the fluctuation in pressure between the needle stopper 357 and the stepped portion 363 is surely relieved by the space 390 between the slit portion 362 a and the inner peripheral portion 359 of the sliding portion 362. And the improvement of this effect is realizable with a simple structure.

  Therefore, also in the third embodiment, since the fluctuation of the pressure between the needle stopper 357 and the stepped portion 363 is surely relieved by the action of the space 390, the fuel injection device 300 can realize the high-speed displacement of the nozzle needle 360. It is.

  In the third embodiment, the cylinder 356 is the “cylindrical member” described in the claims, the needle stopper 357 is the “first regulating portion” described in the claims, and the nozzle needle 360 is described in the claims. In the “valve member”, the slit portion 362a corresponds to the “concave portion” described in the claims, and the stepped portion 363 corresponds to the “first contact portion” described in the claims.

(Fourth embodiment)
As shown in FIGS. 9 and 10, the fourth embodiment of the present invention is another modification of the second embodiment. The fuel injection device 400 according to the fourth embodiment includes a nozzle needle 460 and a cylinder 456 corresponding to the nozzle needle 260 and the cylinder 56 of the second embodiment. Hereinafter, the configuration of the fuel injection device 400 according to the fourth embodiment will be described in detail.

  The nozzle needle 460 of the fourth embodiment has a sliding portion 462 and a stepped portion 463 corresponding to the sliding portion 262 and the stepped portion 263 of the nozzle needle 260 according to the second embodiment. A configuration corresponding to the concave portion 262a in the second embodiment is omitted from the end portion of the sliding portion 462 adjacent to the stepped portion 463.

  The inner peripheral wall portion of the cylinder 456 is provided with an inner peripheral portion 459 and a needle stopper 457 corresponding to the inner peripheral portion 59 and the needle stopper 57 of the second embodiment. The inner peripheral portion 459 is a cylindrical portion that is adjacent to the distal end side of the pressure control chamber 53 and slides the nozzle needle 460 so as to be freely reciprocally displaced along the axial direction. The needle stopper 457 is provided at a portion of the inner peripheral wall portion of the cylinder 456 positioned on the tip side of the inner peripheral portion 459. The needle stopper 457 is formed by enlarging the inner diameter of the inner peripheral wall portion of the cylinder 456, and is located on the radially outer side from the inner peripheral surface of the adjacent inner peripheral portion 459.

  In addition, the cylinder 456 is located between the smallest diameter portion of the inner peripheral portion 459 having the smallest inner diameter and the needle stopper 457, and at the end on the tip side adjacent to the needle stopper 457, together with the sliding portion 462. A recess 459a forming 490 is provided. The concave portion 459a is formed in an annular shape continuously in the circumferential direction of the inner peripheral portion 459 with the radial direction of the cylinder inner peripheral portion 459 as the depth direction. Then, by forming the recess 459a, the inner diameter of the inner peripheral wall portion forming the inner peripheral portion 459 of the cylinder 456 is directed from the portion that directly contacts the sliding portion 462 (FIG. 10 ΦB4) toward the needle stopper 457. It is once thicker (Fig. 10 ΦA4). In addition, the concave portion 459 a has a length in the radial direction, which is the depth direction, shorter than a length in the width direction along the axial direction of the nozzle needle 460. According to the form of the recess 459a, the area where the stepped portion 463 receives the fuel pressure in the space 490 can be reduced while securing the volume of the space 490.

  With the above configuration, a space 490 communicating with the needle stopper 457 and the stepped portion 463 is formed between the cylinder 456 and the nozzle needle 460. Therefore, when the nozzle needle 460 is displaced to the pressure control chamber 53 side, the fuel located between the needle stopper 457 and the stepped portion 463 is repelled between the inner peripheral portion 459 and the sliding portion 462 adjacent to each other. Can be. Therefore, by forming the space 490 between the cylinder 456 and the nozzle needle 460, fluctuations in the pressure between the needle stopper 457 and the stepped portion 463 can be reduced (see the two-dot chain line in FIG. 10). On the other hand, according to the displacement of the nozzle needle 460 toward the tip side, the fuel located in the space 490 can return between the needle stopper 457 and the stepped portion 463. Therefore, fluctuations in pressure drop between the needle stopper 457 and the stepped portion 463 are alleviated.

  Therefore, also in the fourth embodiment, the nozzle generated due to the pressure fluctuation between the needle stopper 457 and the stepped portion 463 is exhibited by the effect of reducing the pressure fluctuation in the space 490 that can be formed by the simple configuration of the recess 459a. The force that hinders the high-speed displacement of the needle 460 can be reduced. Therefore, high-speed displacement of the nozzle needle 460 is realized by the action of the floating plate 270.

  In the fourth embodiment, the cylinder 456 is in the “cylindrical member” in the claims, the needle stopper 457 is in the “first regulating portion” in the claims, and the nozzle needle 460 is in the claims. The stepped portion 463 corresponds to the “valve member” and corresponds to the “first contact portion” recited in the claims.

(Other embodiments)
As mentioned above, although several embodiment by this invention was described, this invention is limited to the said embodiment and is not interpreted and can be applied to various embodiment in the range which does not deviate from the summary.

  In the above embodiment, the displacement direction of the floating plate and the displacement direction of the nozzle needle are the same. However, the present invention may be applied to a fuel injection device in which a floating plate that is displaceable in a direction different from the displacement direction of the nozzle needle is disposed in the pressure control chamber.

  In the embodiment described above, the contact portion 73 formed by the outer peripheral portion of the floating plates 70 and 270 is brought into contact with the plate stopper 58 formed by enlarging the inner peripheral wall portion of the cylinder 56, whereby the displacement of the floating plates 70 and 270 is changed. Was regulated. However, the form which regulates the displacement of the nozzle needle 60 is not limited to this. For example, a floating plate having a configuration corresponding to the “second contact portion” on the outer peripheral wall portion or the outer peripheral portion on the base end side may be used. In addition, the configuration corresponding to the “second regulating portion” is not limited to the cylinder 56 and may be provided in the valve bodies 46 a and 246 and the nozzle body 41. Further, a fuel injection device that does not have a configuration corresponding to the “second regulating portion” and the “second contact portion” may be used.

  In the above-described embodiment, a mechanism for driving the mover 35 with the electromagnetic force of the solenoid 31 is used as the drive unit that opens and closes the pressure control valve 80 that controls the pressure of the fuel in the pressure control chamber 53. However, as long as it is a drive unit that can move according to a control signal from the engine control device 17 and can open and close the pressure control valve 80, a form other than a form using a solenoid, for example, a form using a piezo element may be used.

  In said 1st-3rd embodiment, the space for relieving a pressure was formed by forming a recessed part or a slit part in the sliding part of a nozzle needle. Moreover, in 4th embodiment, the space for relieving a pressure was formed by forming a recessed part in an inner peripheral part. However, both the sliding portion and the inner peripheral portion may have a configuration corresponding to these concave portions.

  In the above, the example which applied this invention to the fuel-injection apparatus used for the diesel engine 20 which injects a fuel directly to the combustion chamber 22 was demonstrated. However, the present invention is not limited to the diesel engine 20 and may be applied to a fuel injection device used for an internal combustion engine such as an Otto cycle engine. In addition, the fuel injected by the fuel injection device is not limited to light oil but may be gasoline, liquefied petroleum gas, or the like. Furthermore, the present invention may be applied to a fuel injection device that injects fuel toward a combustion chamber of an engine that burns fuel such as an external combustion engine.

DESCRIPTION OF SYMBOLS 10 Fuel supply system, 11 Fuel tank, 12 Feed pump, 13 High pressure fuel pump (supply source), 14 Common rail, 14a Branch part, 14b Common rail sensor, 14c Pressure regulator, 12a, 13a, 14e Fuel piping, 14d Supply fuel flow path , 14f Return fuel flow path, 17 Engine control device (control device), 20 Diesel engine, 21 Head member, 22 Combustion chamber, 30 Control valve drive unit, 31 Solenoid, 32 Terminal, 33 Valve seat member, 34 Spring, 35 Movable Child, 36 Stator, 40 Valve body, 41 Nozzle body, 43 Nozzle needle housing part, 44 Injection hole, 45 Valve seat part, 46 First valve body, 47 Second valve body, 246 Valve body, 47a Control valve seat part 48 holder, 48a, 48b length , 48c Socket part, 49 Retaining nut, 49a Step part, 50 Valve part, 52, 252 Inlet side fuel flow path, 52a, 252b Inlet side throttle path, 52b, 252b Open end, 53 Pressure control chamber, 54, 254 Outflow side fuel flow path, 54a, 254b Outflow side throttle flow path, 54b, 254b Open end, 56, 356, 456 Cylinder (cylindrical member), 57, 357, 457 Needle stopper (first regulating part), 58 Plate stopper (Second regulating portion), 59, 359, 459 Cylinder inner peripheral portion (minimum diameter portion), 459a concave portion, 60, 260, 360, 460 nozzle needle (valve member), 61, 261 pressure receiving portion, 62, 262, 362 , 462 Sliding part, 262a Recessed part, 362a Slit part (recessed part), 63, 263, 363, 463 Stepped part (first 1 contact portion), 65 seat portion, 66 return spring, 67 flange member, 70, 270 floating plate (blocking member), 71 throttle channel, 73 contact portion (second contact portion), 76 plate spring, 278 Groove, 80 pressure control valve, 90, 290, 390, 490 space, 100, 300, 400 fuel injection device

Claims (11)

Injection of fuel from a nozzle through a supply fuel flow path is controlled by a valve unit in accordance with a control signal from a control device, and one of the fuel supplied from the supply fuel flow path In the fuel injection device in which the part flows out to the return fuel flow path,
An inflow side fuel flow path communicating with the supply fuel flow path side;
A pressure control chamber having a radial direction defined by a cylindrical member and into which fuel flows from the inflow side fuel flow path;
An outflow side fuel flow path communicating with the return fuel flow path and allowing fuel to flow out of the pressure control chamber;
A first restricting portion that is provided on the opposite side of the cylindrical member to the outflow side fuel flow path side and is located radially outside the minimum diameter portion of the inner peripheral portion of the cylindrical member;
A pressure control valve for controlling the pressure of the fuel in the pressure control chamber by switching communication and blocking between the outflow side fuel flow path and the return fuel flow path in accordance with the control signal;
Displaceably disposed in the pressure control chamber, and when the outflow side fuel passage is switched to the return fuel passage, the communication between the inflow side fuel passage and the pressure control chamber is cut off. A blocking member biased toward the inflow side fuel flow path by the pressure of fuel in the pressure control chamber;
A pressure receiving portion that partitions the valve portion side of the pressure control chamber and receives the pressure of fuel in the pressure control chamber; and a sliding portion that is slidable at the minimum diameter portion of the inner peripheral portion, and the pressure receiving portion A valve member that opens and closes the valve portion by reciprocating in the axial direction of the cylindrical member in accordance with the pressure of the fuel in the pressure control chamber received by the first control portion, facing the first regulating portion in the axial direction. The pressure portion is located on the valve portion side of the sliding portion and on the radially outer side of the sliding portion, and is in contact with the first regulating portion at a position where the pressure receiving portion is separated from the blocking member. A valve member having a first contact portion for restricting displacement toward the control chamber;
A space formed between the cylindrical member and the valve member, and at least in the valve closing state of the valve portion, communicated between the first restricting portion and the first contact portion; In addition, the fuel injection device includes the cylindrical member and a space partitioned by the valve member when the first restricting portion and the first contact portion are in contact with each other.   The valve member includes a concave portion that forms the space between the sliding portion and the first contact portion, and the concave portion has a radial direction of the sliding portion as a depth direction. The fuel injection device according to claim 1.   3. The fuel injection according to claim 2, wherein the recess is continuously formed in an annular shape between the sliding portion and the first contact portion in a circumferential direction of the sliding portion. apparatus.   3. The fuel injection according to claim 2, wherein a plurality of the recesses are formed at intervals in the circumferential direction of the sliding portion between the sliding portion and the first contact portion. apparatus.   The cylindrical member includes a concave portion that forms the space between the inner peripheral portion and the first restricting portion, and the concave portion has a radial direction of the inner peripheral portion as a depth direction. The fuel injection device according to claim 1, wherein the fuel injection device is a fuel injection device.   6. The fuel injection device according to claim 1, wherein the shut-off member is displaceable in the pressure control chamber in a direction along a reciprocal displacement direction of the valve member. The valve member is formed in a cylindrical shape as a whole,
The fuel injection device according to claim 6, wherein the first contact portion is provided in a portion of the outer peripheral wall portion of the valve member that faces the first restricting portion in the axial direction. The first restricting portion is formed by enlarging an inner diameter of the inner peripheral portion of the cylindrical member,
The fuel injection device according to claim 7, wherein the first contact portion is formed by enlarging an outer diameter of an outer peripheral wall portion of the valve member. The cylindrical member has a second restricting portion,
The said interruption | blocking member has a 2nd contact part which regulates the displacement to the said valve member side by contact | abutting to said 2nd control part, The Claim 1 characterized by the above-mentioned. Fuel injectors. The blocking member is formed in a disc shape,
The second restricting portion is provided on the inner peripheral portion of the cylindrical member,
The fuel injection device according to claim 9, wherein the second contact portion is provided on an outer peripheral portion of the blocking member. The second restricting portion is formed by enlarging an inner diameter of the inner peripheral portion of the cylindrical member,
The fuel injection device according to claim 10, wherein the second contact portion is formed on an outer peripheral portion of the blocking member on the valve member side.

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