JP2019199810A - Injection valve - Google Patents

Abstract

To provide an injection valve which can quickly reduce pressure pulsation.SOLUTION: An injection valve (81) has: a first body (15) provided with a first high-pressure passage (R3) through which a high-pressure fluid passes, and slidably supporting a needle valve (20) for opening and closing an injection hole (16) formed at an end part of the first high-pressure passage; and a second body (13) fixed to the first body, and provided with a second high-pressure passage (R3) which communicates with the first high-pressure passage. The injection valve has a chamber (50) in which the high-pressure fluid is accumulated at least at one of the first body and the second body. The chamber is branched from the first high-pressure passage or the second high-pressure passage, and communicates with a branch passage (R5) through which the high-pressure fluid can pass. A throttle part (58) having a smaller flow passage cross section area compared with an area of a connecting face of the chamber to which the branch passage is connected is arranged at the branch passage.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an injection valve that injects high-pressure liquid.

  As a well-known fuel injection system, there is a common rail fuel injection system. In this system, high pressure fuel supplied from a fuel pump is temporarily stored in a common rail (pressure accumulating chamber), and high pressure fuel in the common rail is stored in an injector provided corresponding to each cylinder by a plurality of high pressure passages. Distribute supply. In each injector, the needle valve is moved up and down directly or through a hydraulic servomechanism by driving a built-in actuator. As a result, the nozzle hole provided at the tip of the injector is opened, and high-pressure fuel is injected into the cylinder of the internal combustion engine.

  In such a fuel injection system, a pressure pulsation is generated in the high-pressure passage due to a water hammer effect by closing the needle valve after the injection is completed. In particular, in multi-injection (multi-stage injection), the injection pressure in the second and subsequent stages varies due to the pressure pulsation. As a result, the injection amount fluctuates or the injection amount controllability of multi-injection deteriorates.

  Therefore, in Patent Document 1, a flow path adjusting mechanism is provided at a connection portion between the injector and the common rail so as to reduce pressure pulsation.

JP 2003-262171 A

  However, since the flow path adjustment mechanism of Patent Document 1 is provided at the connection portion between the injector and the common rail, the distance from the pressure pulsation occurrence point (the nozzle hole) is long, and the time until the pressure pulsation is reduced. There was a problem of long.

  This invention is made | formed in view of the said situation, The main objective is to provide the injection valve which can reduce a pressure pulsation quickly.

  In order to solve the above problem, the first means is provided with a first high-pressure passage through which high-pressure liquid passes, and can slide a needle valve that opens and closes a nozzle hole provided at an end of the first high-pressure passage. In the injection valve, the first body and the second body are fixed to the first body, and the second body is fixed to the first body and has a second body formed with a second high pressure passage communicating with the first high pressure passage. At least one of them has a chamber in which the high-pressure liquid is accumulated, and the chamber branches from the first high-pressure passage or the second high-pressure passage and allows the high-pressure liquid to pass therethrough. The passage is in communication with a passage, and the branch passage is provided with a throttle portion having a smaller flow path cross-sectional area than the area of the connecting surface of the chamber to which the branch passage is connected.

  With the above configuration, the pressure pulsation generated in the nozzle hole reaches the chamber from the first high pressure passage or the second high pressure passage through the branch passage. When branching, turbulence occurs and energy loss occurs. That is, pressure pulsation energy is consumed, and pressure pulsation is reduced. Further, when passing through the branch passage, the passage area is changed and the turbulent flow is generated because the passage passes through the throttle portion. Even in this turbulent flow, pressure pulsation energy is consumed and the pressure pulsation is reduced. As described above, pressure pulsation can be reduced with a very simple configuration while suppressing the number of components.

  The chamber is provided in at least one of the first body and the second body. For this reason, compared with the case where a mechanism for reducing pressure pulsation is provided at the base end (the end opposite to the injection hole) of the injection valve, the distance from the injection hole can be shortened, and the pressure pulsation can be quickly performed. Can be reduced.

Sectional drawing of an injector. (A) is an end view which shows the upper end surface of a nozzle body, (b) is an end view which shows the lower end surface of a plate. The figure which shows the relationship between a flow-path cross-sectional area and the amplitude change rate of a pressure pulsation. The figure which shows the relationship between the volume of a chamber, and the amplitude change rate of a pressure pulsation. The time chart which shows the change of the pressure in a nozzle at the time of opening and closing. The figure which shows the injector in another example. The figure which shows the injector in another example. The figure which shows the branch passage in another example. The figure which shows the branch passage in another example. The figure which shows the branch passage in another example. The figure which shows the branch passage in another example.

  Hereinafter, embodiments will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

  FIG. 1 is a diagram showing a fuel injection system 70 in this embodiment. The fuel injection system 70 includes a fuel tank 71, a fuel pump 72, a pressure accumulation chamber 73, a plurality of injectors 81, and a control unit 74. In the figure, one of the plurality of injectors 81 is shown in a cross-sectional view that is enlarged and cut along a cross section passing through the center line. In the present embodiment, each injector 81 corresponds to an injection valve.

  The fuel tank 71 is a tank for storing fuel. A first passage R <b> 1 for supplying the fuel in the fuel tank 71 to the fuel pump 72 is provided between the fuel tank 71 and the fuel pump 72.

  The fuel pump 72 is a pump for increasing the pressure of the fuel (liquid) to obtain the high-pressure fuel H. Between the fuel pump 72 and the pressure accumulation chamber 73, a second passage R <b> 2 for supplying the high-pressure fuel H in the fuel pump 72 to the pressure accumulation chamber 73 is provided.

  The pressure accumulating chamber 73 is for temporarily storing the high-pressure fuel H. In this embodiment, the pressure accumulating chamber 73 is a common rail that supplies the high-pressure fuel H to the plurality of injectors 81. A high-pressure passage R <b> 3 for supplying high-pressure fuel H in the pressure accumulation chamber 73 to the nozzle hole 16 is provided between the pressure accumulation chamber 73 and the nozzle hole 16 at the tip of each injector 81. The high-pressure passage R3 extends from the pressure accumulating chamber 73 and reaches the proximal end portion of the injector 81, and then reaches the nozzle hole 16 at the distal end portion through the inside of the injector 81.

  The injector 81 is a device for injecting the high-pressure fuel H into the cylinder of the internal combustion engine. Between the injector 81 and the fuel tank 71, a low pressure passage R4 for returning the low-pressure fuel to the fuel tank 71 is provided. The low-pressure passage R4 reaches the base end portion of the injector 81 from the middle portion of the injector 81 through the inside of the injector 81, and then extends from the base end portion to the outside of the injector 81 to reach the fuel tank 71. In the figure, only the low pressure passage R4 between one injector 81 and the fuel tank 71 is shown, and the low pressure passage R4 between the other injector 81 and the fuel tank 71 is not shown.

  The control unit 74 is a device that controls the fuel pump 72, each injector 81, and the like. Specifically, the control unit 74 controls each injector 81 to intermittently inject the high-pressure fuel H from each nozzle hole 16 into the cylinder of the internal combustion engine at a desired timing. The combustion of the high-pressure fuel H causes the internal combustion engine to rotate and enter an operating state. In the operation state, the control unit 74 controls the fuel pump 72 to variably control the pressure in the pressure accumulating chamber 73 within a predetermined range (for example, 3 to 20 MPa) as the system control pressure. In the figure, an arrow indicating that the control unit 74 controls only one injector 81 is shown, and the illustration of the arrow is omitted for the other injectors 81.

  Next, the injector 81 will be described in more detail. In the following, for convenience, the distal end side of the injector 81 is referred to as “lower” and the proximal end side is referred to as “upper” in accordance with the drawings. However, the injector 81 is installed with the direction other than the vertical direction set to the distal end side and the base end side, for example, the length direction is inclined with respect to the vertical direction or the length direction is set to the horizontal direction. You can also

  The injector 81 has a body 10, a needle valve 20, a valve drive mechanism 30, and a drive control mechanism 40.

  The body 10 includes a main body 11 disposed on the proximal end side of the injector 81, a plate 13 connected to the main body 11, a nozzle body 15 connected to the plate 13, and a retainer mounted so as to cover them. And a ning nut 18. The main body 11 constitutes the upper part of the body 10. The main body 11 is a columnar member that is long in the vertical direction, and a hole that forms part of the high-pressure passage R3 penetrates in the vertical direction.

  The nozzle body 15 constitutes the lower part of the body 10. The nozzle body 15 is a cylindrical member that is long in the vertical direction, and the needle valve 20 is accommodated and supported in the cylindrical hole so as to be displaceable (slidable) in the vertical direction. A gap between the nozzle body 15 and the needle valve 20 constitutes a part of the high-pressure passage R3. The nozzle hole 16 is formed at the lower end of the nozzle body 15. For this reason, the high-pressure passage R3 penetrates the nozzle body 15 in the vertical direction. The nozzle body 15 corresponds to the first body, and the high-pressure passage R3 formed in the nozzle body 15 corresponds to the first high-pressure passage.

  The plate 13 is interposed between the main body 11 and the nozzle body 15. The plate 13 is a disk-shaped member, and a hole constituting a part of the high-pressure passage R3 penetrates in the vertical direction. The plate 13 corresponds to the second body, and the high-pressure passage R3 formed in the plate 13 corresponds to the second high-pressure passage.

  The retaining nut 18 is a cylindrical member provided on the outer peripheral side of the lower portion of the main body 11, the plate 13, and the upper portion of the nozzle body 15. The retaining nut 18 fastens the nozzle body 15 and the plate 13 to the main body 11.

  The needle valve 20 is a cylindrical member. The needle valve 20 is configured to stop the injection of the high-pressure fuel H by closing the injection hole 16. The lower part of the cylindrical needle cylinder 23 is fitted on the upper part of the needle valve 20. The needle valve 20 is pressed upward by the pressure in the high pressure passage R3.

  The valve drive mechanism 30 is a mechanism for driving the needle valve 20 up and down, and is provided inside the nozzle body 15. The valve drive mechanism 30 includes a needle spring 31 that urges the needle valve 20 downward with elastic force, and a pressure chamber 32 that presses the needle valve 20 downward with internal pressure. The needle spring 31 is interposed between the needle cylinder 23 and the needle valve 20, and urges the needle cylinder 23 upward by a reaction force that urges the needle valve 20 downward.

  The pressure chamber 32 is formed in a partition between the upper end surface of the needle valve 20, the inner peripheral surface of the needle cylinder 23, and the lower end surface of the plate 13. The pressure chamber 32 communicates with the high-pressure passage R <b> 3 through an import 33 provided in the plate 13. The import 33 is provided with an in-orifice 34. Further, the pressure chamber 32 communicates with the low pressure passage R4 via an out port 35 provided in the plate 13. An out orifice 36 is provided in the out port 35.

  The drive control mechanism 40 is a mechanism that controls the pressure in the pressure chamber 32, and is provided in the main body 11. The drive control mechanism 40 includes a valve body 41, an armature 43, a valve body 44, a valve spring 47, and an actuator 48.

  The valve body 41 supports the armature 43 so as to be slidable in the vertical direction. The armature 43 accommodates the valve body 44 at the lower end. The valve body 44 is provided above the opening on the upper side of the out orifice 36, and blocks the communication between the pressure chamber 32 and the low pressure passage R4 by closing the opening. The valve spring 47 urges the armature 43 downward. The actuator 48 is a device for driving the armature 43 upward. The actuator 48 is an electromagnetic solenoid in the present embodiment, but may be another one such as a piezo actuator. The actuator 48 is controlled based on a control signal given from the control unit 74.

  Next, the operation of the injector 81 will be described. In a state where the actuator 48 is not energized (the state shown in FIG. 1), the armature 43 and the valve body 44 are lowered by the urging force of the valve spring 47. Therefore, the valve body 44 blocks the opening of the out orifice 36. Accordingly, the pressure in the pressure chamber 32 is high because the pressure supplied from the in-orifice 34 is accumulated. In this state, the force that presses the needle valve 20 downward by the pressure in the pressure chamber 32 and the elastic force of the needle spring 31 exceeds the force that presses the needle valve 20 upward by the pressure in the high-pressure passage R3 or the like. Therefore, the needle valve 20 is lowered and closes the nozzle hole 16 at the lower end. That is, the needle valve 20 is closed.

  From this state (the state shown in FIG. 1), when the actuator 48 is energized, the actuator 48 attracts the armature 43 upward. As a result, the armature 43 and the valve body 44 are raised, and the valve body 44 is separated from the opening of the out orifice 36, thereby opening the opening. Thereby, the pressure in the pressure chamber 32 falls by the pressure in the pressure chamber 32 flowing out into the low pressure passage R4. For this reason, the force that presses the needle valve 20 downward becomes lower than the force that presses the needle valve 20 upward due to the pressure in the high-pressure passage R3 or the like. As a result, the needle valve 20 rises and the lower end portion of the needle valve 20 is separated from the nozzle hole 16. That is, the needle valve 20 is opened. As a result, the high-pressure fuel H is injected from the injection hole 16. When the energization is stopped from this state, the needle valve 20 is lowered again to close the valve, and the injection ends.

  By the way, when the needle valve 20 is closed, pressure pulsation is generated in the high-pressure passage R3 due to water hammer. When pressure pulsation occurs, it becomes difficult to perform fuel injection appropriately. This is particularly problematic when performing multistage injection with a short injection interval. Therefore, the injector 81 includes a mechanism for reducing pressure pulsation at an early stage.

  More specifically, the injector 81 has a chamber 50 in which the high-pressure fuel H is accumulated inside the body 10. The chamber 50 is provided inside the nozzle body 15 and the plate 13. More specifically, inside the nozzle body 15, there is provided a first recess 50a that opens to the upper end surface 15a of the nozzle body 15 and is formed in a groove shape along the vertical direction. Inside the plate 13, there is provided a second recess 50 b that opens to the lower end surface 13 a of the plate 13 and is formed in a groove shape along the vertical direction. In addition, the shape of the opening part of the 1st recessed part 50a and the opening part of the 2nd recessed part 50b are in agreement. Further, the upper end surface 15 a of the nozzle body 15 corresponds to a connection surface connected to the lower end surface 13 a of the plate 13, and the lower end surface 13 a of the plate 13 corresponds to a connection surface connected to the upper end surface 15 a of the nozzle body 15.

  In a state where the nozzle body 15 and the plate 13 are connected, the nozzle body 15 and the plate 13 are fixed so that the opening portion of the first recess 50a and the opening portion of the second recess 50b coincide. In this state, the first recess 50a is closed by the second recess 50b, and a space surrounded by the first recess 50a and the second recess 50b is formed. This space corresponds to the chamber 50. That is, it can be said that the chamber 50 is provided so as to communicate from the nozzle body 15 to the plate 13.

  As shown in FIG. 2, the chamber 50 is provided in an annular shape so as to surround the high-pressure passage R3 on the radially outer side of the high-pressure passage R3 (and the needle valve 20 accommodated in the high-pressure passage R3) in the nozzle body 15. It has been. In FIG. 2A, illustration of the needle valve 20 and the valve drive mechanism 30 accommodated in the high pressure passage R3 of the nozzle body 15 is omitted. 1 and 2, the presence of the high-pressure fuel H is indicated by dot hatching.

  The chamber 50 communicates with a branch passage R5 branched from the high-pressure passage R3 in the nozzle body 15. As shown in FIG. 2A, the branch passage R5 is provided in plural (eight in this embodiment), and is provided radially around the high-pressure passage R3. At that time, a plurality of branch passages R5 are provided at a predetermined angular interval (in the present embodiment, an interval of 45 degrees). One end of the branch passage R5 is branched from the high-pressure passage R3, and the high-pressure fuel H flowing through the high-pressure passage R3 flows in or out. The other end of the branch passage R5 communicates with the chamber 50. For this reason, the high pressure fuel H flows into or out of the chamber 50 from the high pressure passage R3 via the branch passage R5. That is, the high-pressure fuel H is always accumulated in the chamber 50.

  A narrowing portion 58 is formed in the branch passage R5. More specifically, the branch passage R5 is formed with a narrowed portion 58 having a smaller flow path cross-sectional area than the area of the connection surface of the chamber 50 to which the end of the branch passage R5 is connected. The connection surface of the chamber 50 to which the end of the branch passage R5 is connected is an inner wall surface in the annular chamber 50. The throttle 58 is provided over the entire branch passage R5 (that is, from the chamber 50 to the high-pressure passage R3).

  This branch passage R5 is formed on the nozzle body 15 side. More specifically, the nozzle body 15 is provided with a groove that opens to the upper end surface 15a of the nozzle body 15, and the groove 13 is closed by the lower end surface 13a of the plate 13, thereby forming a branch passage R5. . That is, the branch passage R <b> 5 can be said to be a passage surrounded by the groove formed in the nozzle body 15 and the lower end surface 13 a of the plate 13.

  Next, the function of the chamber 50 will be described. Immediately after the needle valve 20 is opened (time point T1), the pressure supply from the pressure accumulation chamber 73 to the high pressure passage R3 is not in time, so that the pressure in the high pressure passage R3 decreases. This decrease is particularly remarkable in the vicinity of the nozzle hole 16. In such a case, the pressure is supplied from the chamber 50 to the high pressure passage R3 via the branch passage R5. That is, the chamber 50 acts as a small pressure accumulation chamber. Therefore, as shown in the region P1 surrounded by the broken line in FIG. 5, the pressure drop in the high pressure passage R3 is suppressed, and the pressure pulsation generated by the pressure drop is also reduced. In FIG. 5, the nozzle internal pressure at the time of opening and closing in the injector 81 of the present embodiment is indicated by a solid line. On the other hand, the pressure in the nozzle at the time of opening and closing in the injector in which the chamber 50 does not exist is indicated by a broken line.

  After the needle valve 20 is closed (time T2), the pressure pulsation generated from the vicinity of the nozzle hole 16 propagates back to the upper side (base end side) of the high pressure passage R3. Then, at least a part of the pressure pulsation branches to the chamber 50 side in the branch passage R5. When this branching is performed, turbulent flow is generated, so that energy of pressure pulsation is consumed. That is, pressure pulsation is reduced.

  Further, when passing through the branch passage R5, friction (shear resistance friction) due to the viscosity of the high-pressure fuel H is generated, and energy of pressure pulsation is consumed. Further, a narrowed portion 58 is formed in the branch passage R5 over the entire area.

  As shown in FIG. 3, the throttle portion 58 has a predetermined flow path cross-sectional area so that pressure pulsation is most easily reduced (that is, the influence of friction due to viscosity is large and the flow rate is appropriate). (X). For this reason, when passing through the throttle part 58 of the branch passage R5, compared with a case where it is smaller (or larger) than the predetermined flow path cross-sectional area (X), it is greatly affected by friction (shear resistance friction), and pressure The energy that the pulsation has is consumed more. In FIG. 3, the horizontal axis indicates the size of the flow path cross-sectional area of the throttle portion 58 and the vertical axis indicates the rate of change in pressure pulsation amplitude. It shows that the fall of pressure pulsation is so large that an amplitude change rate is large on the minus side (lower side).

  A plurality (eight in this embodiment) of branch passages R5 are provided. By providing a plurality, the number of branches increases, and accordingly, turbulent flow due to the branches tends to occur. Furthermore, the length of the throttle portion 58 can be increased, and energy consumption due to friction can be increased.

  When the pressure pulsation reaches the chamber 50 through the restricting portion 58, turbulent flow is generated due to the change in the cross-sectional area of the flow path. When the pressure pulsation reaches and the pressure in the chamber 50 becomes higher than the pressure in the high pressure passage R3, the high pressure fuel H moves from the chamber 50 to the high pressure passage R3 via the branch passage R5. By repeating this phenomenon, the energy of pressure pulsation is consumed based on turbulence and friction. As described above, as shown by a region P2 surrounded by a broken line in FIG. 5, the pressure pulsation is also reduced early compared to the conventional example.

  In addition, as shown in FIG. 4, when the chamber 50 is enlarged, the energy which a pressure pulsation has is easy to be consumed, and a pressure pulsation is easy to be reduced compared with the case where it is small. In FIG. 4, the magnitude of the volume of the chamber 50 is indicated on the horizontal axis, and the amplitude change rate of the pressure pulsation is indicated on the vertical axis. More specifically, when the chamber 50 is enlarged, the pressure in the chamber 50 is less likely to change than when the chamber 50 is small. For this reason, the differential pressure between the high-pressure passage R3 and the chamber 50 is difficult to decrease. As a result, the high-pressure fuel H easily goes back and forth between the high-pressure passage R3 and the chamber 50, and turbulence and friction are generated in the process, and pressure pulsation is easily reduced.

  Therefore, in this embodiment, the chamber 50 is provided so as to communicate from the nozzle body 15 to the plate 13. For this reason, the chamber 50 has a larger volume than that provided in either the nozzle body 15 or the plate 13. And the chamber 50 is comprised cyclically | annularly in those radial direction outer sides so that high pressure channel | path R3 and the needle valve 20 may be avoided. For this reason, the chamber 50 can be provided so as to extend in the vertical direction without being obstructed by the high pressure passage R3 and the needle valve 20, and compared with the case where the chamber 50 is provided so as to overlap the high pressure passage R3 and the needle valve 20, The volume is increasing. Thereby, pressure pulsation is easily reduced earlier.

  According to the embodiment described above in detail, the following excellent effects can be obtained.

  The injector 81 has a chamber 50 in which the high-pressure fuel H is accumulated inside the nozzle body 15 and the plate 13. The chamber 50 branches from the high pressure passage R3 and communicates with the branch passage R5 through which the high pressure fuel H can pass. The branch passage R5 is provided with a throttle portion 58 having a smaller flow path cross-sectional area than the area of the connection surface of the chamber 50 to which the branch passage R5 is connected. With this configuration, the pressure pulsation generated in the nozzle hole 16 reaches the chamber 50 from the high pressure passage R3 via the branch passage R5. When branching, turbulent flow is generated and energy loss due to pressure pulsation occurs. That is, pressure pulsation energy is consumed, and pressure pulsation is reduced. Further, when passing through the branch passage R5, since it passes through the throttle portion 58, turbulent flow is generated based on the change in the flow path cross section. Even in this turbulent flow, pressure pulsation energy is consumed and the pressure pulsation is reduced. As described above, pressure pulsation can be reduced with a very simple configuration while suppressing the number of components.

  The chamber 50 is provided inside the nozzle body 15 and the plate 13. For this reason, compared with the case where the mechanism for reducing pressure pulsation is provided in the base end (end part on the opposite side to the injection hole 16) of the injector 81, distance from the injection hole 16 can be shortened, and pressure pulsation Can be quickly reduced.

  The chamber 50 has an opening that opens to the connection surface between the nozzle body 15 and the plate 13, and the opening is closed by connecting the nozzle body 15 and the plate 13. That is, the nozzle body 15 is provided with a first recess 50 a that opens to the upper end surface 15 a of the nozzle body 15. The plate 13 is provided with a second recess 50 b that opens to the lower end surface 13 a of the plate 13. Then, in a state where the nozzle body 15 and the plate 13 are connected, a chamber 50 surrounded by the first recess 50a and the second recess 50b is formed. For this reason, when providing the 1st recessed part 50a and the 2nd recessed part 50b, the upper end surface 15a of the nozzle body 15 and the lower end surface 13a of the plate 13 should just be processed, and processing is easy. That is, the pressure pulsation can be quickly reduced with a simple configuration.

  As the volume of the chamber 50 is larger, a pressure change is less likely to occur in the chamber 50. That is, the differential pressure based on pressure pulsation between the chamber 50 and the high-pressure passage R3 is difficult to decrease. For this reason, the liquid easily flows in and out between the chamber 50 and the high-pressure passage R3 via the branch passage R5, and the energy loss opportunity of the pressure pulsation can be increased. Therefore, pressure pulsation can be quickly reduced. Therefore, the chamber 50 is provided so as to communicate from the nozzle body 15 to the plate 13. Furthermore, the chamber 50 was provided in an annular shape so as to surround the needle valve 20 and the high-pressure passage R3 on the radially outer side. The volume of the chamber 50 was increased as much as possible to quickly reduce the pressure pulsation.

  The throttle portion 58 is provided over the entire branch passage R5. The throttle portion 58 is provided with a predetermined flow path cross-sectional area so that the influence of friction due to viscosity is large and an appropriate flow rate is obtained. For this reason, the longer the throttle portion 58, the greater the energy loss of pressure pulsation due to friction. Therefore, the throttle portion 58 is provided over the entire branch passage R5. Thereby, the energy loss by friction can be increased and pressure pulsation can be reduced rapidly.

  The energy loss of turbulent flow due to branching can be increased when the number of branch passages R5 is larger than when the number of branch paths R5 is small. In addition, the larger the number of branched flow paths, the larger the liquid contact area in the branch passage R5, compared to the case where there are few. That is, it becomes easy to increase the energy loss of pressure pulsation due to friction. Therefore, a plurality of branch passages R5 are provided to quickly reduce pressure pulsation.

  As shown in FIG. 3, the flow path cross-sectional area of the throttle portion 58 is desirably a predetermined size, and energy loss due to friction is small, whether it is smaller or larger. Therefore, when forming the branch passage R5, it is desirable that the structure be easily processed. Therefore, the branch passage R5 is provided only in the nozzle body 15 and has an opening that opens at the upper end surface 15a of the nozzle body 15 (the connection surface with the plate 13 on the nozzle body 15 side). . And by connecting the nozzle body 15 and the plate 13, the opening part of this branch channel | path R5 is obstruct | occluded, and the branch channel | path R5 is formed.

  As a result, compared to the case where the branch passage R5 is provided on both sides of the nozzle body 15 and the plate 13, when the nozzle body 15 is provided only, manufacturing errors (for example, assembly errors and dimensional errors) are reduced, and processing is performed. Can be facilitated and the processing accuracy can be improved. In addition, since it is provided so as to open at the connection surface (upper end surface 15a), the processing becomes easy and the accuracy can be further improved. As described above, the flow path cross-sectional area can be set to an appropriate size in the throttle portion 58 of the branch passage R5, and the energy loss due to friction can be increased.

(Other embodiments)
It is not limited to the said embodiment, For example, you may implement as follows. In addition, below, the same code | symbol is attached | subjected to the part which is mutually the same or equivalent in each embodiment, The description is used about the part of the same code | symbol.

  In the above embodiment, the configuration of the injector 81 may be changed as appropriate. For example, as shown in FIG. 6, a high pressure passage R3 and a needle valve 20 that is slidably supported in the high pressure passage R3 so as to penetrate from the nozzle body 15 of the injector 81 to the lower body 100 that is the second body are provided. It may be provided. Also in this case, the chamber 50 communicating from the nozzle body 15 to the lower body 100 can be provided in an annular shape so as to surround the radially outer side of the needle valve 20 as in the above embodiment.

  Further, for example, as shown in FIG. 7A, the electromagnetic valve 202 may be used to control the back pressure of the pressure chamber 32, thereby adopting the injector 81 that slides the needle valve 20. In this case, as shown in FIG. 7B, the chamber 50 may be formed in an arc shape so as to avoid the high-pressure passage R3 when viewed in the vertical direction. A branch passage R5 that branches from the high-pressure passage R3 to the chamber 50 may be provided.

  In the above embodiment, the shape of the branch passage R5 may be arbitrarily changed. For example, as shown in FIG. 8, the branch passage R5 may be provided in a curved shape. At that time, it may meander. By providing the curved shape, turbulent flow is generated when passing through the branch passage R5, and energy loss based on the turbulent flow can be increased. Moreover, by making it curve shape, compared with the case where it provides in linear form, it becomes easy to lengthen the length of the branch channel | path R5. That is, it becomes easy to increase energy loss due to friction. As described above, pressure pulsation can be reduced more quickly.

  In the above embodiment, as shown in FIG. 9, the branch passage R5 may be further branched in the middle. Thereby, the turbulent flow loss based on a branch can be enlarged.

  In the above embodiment, it is not necessary to provide the throttle portion 58 over the entire area of the branch passage R5. For example, as shown in FIG. 9, a constricted portion 58 may be provided at a connection portion (one end of the branch passage R5) between the chamber 50 and the branch passage R5. Further, as shown in FIG. 10, a plurality (two in the figure) of the narrowed portions 58 may be provided in the branch passage R5. By making it like FIG. 10, a turbulent flow loss can be enlarged.

  In the above embodiment, as shown in FIG. 11, an annular branch passage R <b> 5 may be provided between the high pressure passage R <b> 3 and the chamber 50. FIG. 11 is a view when the upper end surface 15a of the injector 81 is viewed from the vertical direction. That is, the branch passage R5 communicates with the entire outer periphery of the high-pressure passage R3 and communicates with the entire inner periphery of the chamber 50. In the vertical direction, the height of the branch passage R5 is extremely low (thin) compared to the chamber 50, as in FIG. Even with such a simple configuration, it is possible to obtain the same effects as in the above embodiment.

-In the said embodiment, while providing an unevenness | corrugation in the inner wall of branch passage R5, while being easy to generate | occur | produce a turbulent flow, you may improve a frictional force. For example, the upper end surface 15a of the nozzle body 15 may be provided with irregularities on the bottom surface of the branch passage R5.
In the above embodiment, the chamber 50 may be provided in at least one of the nozzle body 15 and the plate 13.

  -In the said embodiment, as long as it is an injection valve which injects a high voltage | pressure liquid, you may apply to the injection valve which injects another liquid. For example, the present invention may be applied to an injection valve that injects a high-pressure reducing agent (such as urea water).

  DESCRIPTION OF SYMBOLS 13 ... Plate, 15 ... Nozzle body, 16 ... Injection hole, 20 ... Needle valve, 50 ... Chamber, 58 ... Throttling part, 81 ... Injector, R3 ... High pressure passage, R5 ... Branch passage

Claims (8)

A first high-pressure passage (R3) through which a high-pressure liquid passes is provided, and a first high-pressure passage (R3) that slidably supports a needle valve (20) that opens and closes a nozzle hole (16) provided at an end of the first high-pressure passage. In the injection valve (81) having one body (15), and a second body (13) fixed to the first body and formed with a second high pressure passage (R3) communicating with the first high pressure passage,
A chamber (50) in which the high-pressure liquid is accumulated in at least one of the first body and the second body;
The chamber is branched from the first high-pressure passage or the second high-pressure passage and communicates with a branch passage (R5) through which the high-pressure liquid can pass.
The injection valve provided with the throttle part (58) whose flow path cross-sectional area is small compared with the area of the connection surface of the chamber to which the branch path is connected.   The chamber has an opening that opens to a connection surface (15a, 13a) between the first body and the second body, and the first body and the second body are connected to each other. The injection valve according to claim 1, wherein the opening is closed.   The injection valve according to claim 1, wherein the chamber is provided from the first body to the second body.   The said throttle part is an injection valve of any one of Claims 1-3 provided over the whole region of the said branch passage.   The injection valve according to any one of claims 1 to 4, wherein a plurality of the branch passages are provided.   The injection valve according to any one of claims 1 to 5, wherein the branch passage is provided in a curved shape.   The branch passage is provided in one of the first body and the second body, and with respect to the connection surface (15a, 13a) between the first body and the second body. The opening part of the said branch passage is obstruct | occluded by the said 1st body or the said 2nd body by having the opening part opened and connecting the said 1st body and the said 2nd body. The injection valve according to any one of 1 to 6.   The injection valve according to claim 1, wherein the chamber is provided so as to surround the needle valve on a radially outer side of the needle valve.

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