JP2012132322A - Injector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress an increase in a sliding clearance 13 formed on an outer circumference of a nozzle needle in an injection nozzle of an injector.SOLUTION: Three high-pressure introduction passages 47a-47c in which high-pressure fuel is introduced are provided around the sliding clearance 13 separately from a side passage 10. Consequently, a high-pressure flowing region in which the high-pressure fuel flows is divided into four sections of the side passage 10 and the high-pressure introduction passages 47a-47c on the outer peripheral side of the sliding clearance 13. Thus, the sliding clearance 13 can be annularly surrounded by the high-pressure flowing region, so that deformation of a sliding face on the nozzle body 7 side forming the sliding clearance 13 toward the outside diameter side, which is caused by the high fuel pressure in the high-pressure flowing region is suppressed. As a result, the increase in the sliding clearance 13 can be suppressed even when the pressure of the fuel passing through the sliding clearance 13 is increased as the injection pressure is increased.

Description

  The present invention relates to an injector for injecting and supplying fuel to an engine.

Conventionally, it is known that an injector 100 that injects and supplies fuel with an ultrahigh injection pressure exceeding 100 MPa includes an injection nozzle 101 as shown in FIG. 4 (see, for example, Patent Document 1).
That is, the injector 100 includes an injection nozzle 101 that injects high-pressure fuel, and a main body (not shown) that receives high-pressure fuel from a fuel supply source and guides the high-pressure fuel to the injection nozzle 101. It is configured by fastening to the tip.

The injection nozzle 101 includes a nozzle body 103 having an injection hole 102 at the tip, and a nozzle needle 104 that is accommodated in the nozzle body 103 and supported so as to be slidable in the axial direction.
The nozzle body 103 includes an accommodation hole 105 that accommodates and accommodates the nozzle needle 104 slidably in the axial direction, and a side that opens to connect to the accommodation hole 105 from the side and opens to the rear end of the nozzle body 103. The nozzle hole 102 is open at the tip of the accommodation hole 105.

  The injection nozzle 101 is fastened to the main body so that a main body side high-pressure channel (not shown) for guiding high-pressure fuel in the main body and the side passage 106 communicate with each other. Accept high pressure fuel.

Here, the nozzle body 103 and the nozzle needle 104 constitute a sliding support structure of the nozzle needle 104 at the rear end side of the accommodation hole 105 from the position where the side path 106 opens, thereby forming a sliding clearance 107. In addition, a tip-side flow path 108 that leads high-pressure fuel to the nozzle hole 102 is formed on the tip side of the sliding clearance 107.
The nozzle needle 104 starts or stops fuel injection by moving in the axial direction and opening and closing between the front end side flow path 108 and the injection hole 102.

By the way, in the injector 100, the following situations are regarded as problems as the injection pressure increases.
That is, the fuel in the front end side flow path 108 leaks through the sliding clearance 107 to a low pressure chamber (not shown) formed on the rear end side of the nozzle needle 104, but when the injection pressure increases, the sliding clearance is increased. Since the fuel passing through 107 also has a high pressure, the sliding clearance 107 is pushed wide. As a result, it is assumed that the amount of fuel leaking from the front end side channel 108 to the low pressure chamber will increase, and such a situation will be considered as a problem as the injection pressure increases. It is done.

JP-A-2-112666

  The present invention has been made to solve the above-described problems, and an object thereof is to suppress an increase in sliding clearance formed on the outer periphery of a nozzle needle in an injection nozzle of an injector.

[Means of Claim 1]
The injector according to claim 1 includes an injection nozzle that injects high-pressure fuel, and a main body that receives high-pressure fuel from a fuel supply source, and is configured by fastening the injection nozzle to the front end side in the axial direction of the main body. Yes.
The injection nozzle includes a nozzle body having an injection hole at the tip, and a nozzle needle that is accommodated in the nozzle body and is slidably supported in the axial direction. The nozzle body has a housing hole that supports and accommodates the nozzle needle so as to be slidable in the axial direction, and a side path that opens to the housing hole from the side and opens to the rear end of the nozzle body. The nozzle hole opens at the tip of the accommodation hole.

The injection nozzle is fastened to the main body so that the main body-side high-pressure channel for guiding high-pressure fuel in the main body and the side passage communicate with each other, and receives the high-pressure fuel from the main body into the accommodation hole through the side passage.
Here, the nozzle body and the nozzle needle constitute a sliding support structure of the nozzle needle on the rear end side from the position where the side path opens in the accommodation hole to form a sliding clearance. Also, a tip-side flow path that guides high-pressure fuel to the nozzle hole is formed on the tip side.

The nozzle needle starts or stops fuel injection by moving in the axial direction and opening and closing between the tip side flow path and the injection hole.
Further, a high-pressure introduction path through which high-pressure fuel is introduced is provided around the sliding clearance in addition to the side path.

  As a result, a high-pressure flow region in which high-pressure fuel flows, such as a side passage and a high-pressure introduction passage, is formed in a plurality of portions on the outer peripheral side of the sliding clearance. For this reason, since the sliding clearance can be annularly surrounded by the high-pressure flow region, the sliding surface on the nozzle body side that forms the sliding clearance is deformed to the outer diameter side by the high fuel pressure in the high-pressure flow region. Can be suppressed.

  As a result, in the injection nozzle of the injector, even if the fuel passing through the sliding clearance is increased as the injection pressure is increased, the expansion of the sliding clearance formed on the outer periphery of the nozzle needle can be suppressed.

[Means of claim 2]
According to the injector of the second aspect, the side passage and the high pressure introduction passage communicate with each other, and the fuel pressure introduced into each of the side passage and the high pressure introduction passage is made uniform.
Thereby, since the fuel pressure in the high-pressure flow region can be made uniform in the circumferential direction, variation in deformation suppression of the sliding surface on the nozzle body side can be suppressed in the circumferential direction.

[Means of claim 3]
According to the injector of the third aspect, the distal end side flow passage is provided with the bag portion that expands in the radial direction, and the side passage is connected to the bag portion to open. And the high voltage | pressure introduction path is connecting with the side path by opening to a bag part.
As a result, the high pressure introduction path can be provided, for example, by drilling with a single drill, and the side path and the high pressure introduction path can be communicated with each other, so that the manufacturing process of the injector can be simplified.

[Means of claim 4]
According to the injector of the fourth aspect, the high pressure introduction path opens at the rear end of the nozzle body. The side passage and the high pressure introduction passage communicate with each other through a groove provided at the rear end of the nozzle body.
As a result, the fuel pressure in the high-pressure flow region can be made more uniform in the circumferential direction.

It is a whole block diagram of an injector (Example 1). (A) is a top view of a nozzle body, (b) is AA sectional drawing of (a) (Example 1). (A) is a top view of a nozzle body, (b) is BB sectional drawing of (a) (Example 2). (A) is a top view of a nozzle body, (b) is CC sectional drawing of (a) (conventional example).

The injector according to the first embodiment includes an injection nozzle that injects high-pressure fuel and a main body that receives high-pressure fuel from a fuel supply source, and is configured by fastening the injection nozzle to the front end side in the axial direction of the main body. .
The injection nozzle includes a nozzle body having an injection hole at the tip, and a nozzle needle that is accommodated in the nozzle body and is slidably supported in the axial direction. The nozzle body has a housing hole that supports and accommodates the nozzle needle so as to be slidable in the axial direction, and a side path that opens to the housing hole from the side and opens to the rear end of the nozzle body. The nozzle hole opens at the tip of the accommodation hole.

  The injection nozzle is fastened to the main body so that the main body-side high-pressure channel for guiding high-pressure fuel in the main body and the side passage communicate with each other, and receives the high-pressure fuel from the main body into the accommodation hole through the side passage. Here, the nozzle body and the nozzle needle constitute a sliding support structure of the nozzle needle on the rear end side from the position where the side path opens in the accommodation hole to form a sliding clearance. Also, a tip-side flow path that guides high-pressure fuel to the nozzle hole is formed on the tip side.

The nozzle needle starts or stops fuel injection by moving in the axial direction and opening and closing between the tip side flow path and the injection hole.
Further, a high-pressure introduction path through which high-pressure fuel is introduced is provided around the sliding clearance in addition to the side path.

Further, the side passage and the high pressure introduction passage communicate with each other, and the fuel pressure introduced into each of the side passage and the high pressure introduction passage is made uniform.
Furthermore, the front end side flow path is provided with a bag portion that expands in the radial direction, and a side path is connected to the bag portion to open. And the high voltage | pressure introduction path is connecting with the side path by opening to a bag part.

  According to the injector of the second embodiment, the high-pressure introduction path opens at the rear end of the nozzle body. The side passage and the high pressure introduction passage communicate with each other through a groove provided at the rear end of the nozzle body.

[Configuration of Example 1]
The structure of the injector 1 of Example 1 is demonstrated using FIG. 1 and FIG.
The injector 1 can inject and supply fuel with an ultrahigh injection pressure exceeding 100 MPa. For example, the injector 1 directly injects and supplies fuel into a cylinder of a diesel engine (not shown).

The injector 1 includes an injection nozzle 2 that injects high-pressure fuel, a main body 3 that receives high-pressure fuel from a fuel supply source such as a common rail and guides the high-pressure fuel to the injection nozzle 2, and an electromagnetic actuator 4 that opens the injection nozzle 2. The injection nozzle 2 is fastened to the front end side of the main body 3 in the axial direction, and the electromagnetic actuator 4 is fastened to the rear end side of the main body 3 in the axial direction.
The injection nozzle 2 and the electromagnetic actuator 4 are fastened to the main body 3 by screw fastening with retaining nuts 5A and 5B, respectively.

The injection nozzle 2 has a nozzle body 7 having an injection hole 6 at the tip, and a nozzle needle 8 that is accommodated in the nozzle body 7 and supported slidably in the axial direction.
The nozzle body 7 includes an accommodation hole 9 that supports and accommodates the nozzle needle 8 slidably in the axial direction, and a side that opens to connect to the accommodation hole 9 from the side and opens to the rear end of the nozzle body 7. The nozzle hole 6 is opened at the tip of the accommodation hole 9.

  The injection nozzle 2 is fastened to the main body 3 so that the high-pressure flow path 12 on the main body 3 side that guides high-pressure fuel to the injection nozzle 2 and the side path 10 communicate with each other, and is received from the main body 3 through the side path 10. High pressure fuel is received in the hole 9. Here, the nozzle body 7 and the nozzle needle 8 constitute a sliding support structure of the nozzle needle 8 in the receiving hole 9 on the rear end side with respect to the position where the side passage 10 opens, and form a sliding clearance 13. In addition, a tip-side flow path 14 that guides high-pressure fuel to the nozzle hole 6 on the tip side with respect to the sliding clearance 13 is formed. Moreover, the bag part 14a which expands to radial direction is provided in the front end side flow path 14, and the side path 10 is connected and opened to the bag part 14a.

  Thus, the side passage 10, the front end side passage 14, and the bag portion 14a form the high pressure passage 12 on the injection nozzle 2 side through which the high pressure fuel received from the main body 3 flows, and the high pressure passage on the injection nozzle 2 side. The 12 fuel leaks into the low-pressure chamber 15 formed in the main body 3 through the sliding clearance 13.

  In addition, a sheet surface 17 on which the sheet portion 16 provided at the distal end of the nozzle needle 8 is attached and detached is provided at the distal end of the accommodation hole 9, and the injection hole 6 is disposed further on the distal end side than the sheet surface 17. 9 is open. For this reason, when the seat portion 16 is attached to and detached from the seat surface 17, the injection hole is started and stopped by opening and closing between the nozzle hole 6 and the front end side flow path 14.

The main body 3 forms a fuel chamber 19 into which high-pressure fuel flows at the rear end. Then, the fuel pressure in the fuel chamber 19 increases or decreases according to the operation of the electromagnetic actuator 4, thereby stopping or starting the fuel injection by the injection nozzle 2 (hereinafter, the fuel chamber 19 is referred to as a control chamber 19). ).
That is, the main body 3 has a command piston 20 that transmits the fuel pressure of the control chamber 19 to the nozzle needle 8 of the injection nozzle 2 and a main body 21 that houses the command piston 20 and supports it slidably in the axial direction. . Further, the main body 21 has an accommodation hole 22 for accommodating the command piston 20 so as to be slidable in the axial direction.

  Further, the command piston 20 and the main body 21 constitute a sliding support structure of the command piston 20 in the accommodation hole 22 to form a sliding clearance 23, and the hole area on the rear end side of the sliding clearance 23 is liquid-filled. By densely partitioning, the control chamber 19 is formed, and the fuel pressure in the control chamber 19 is applied to the command piston 20 in the axial direction. Then, the fuel pressure in the control chamber 19 is increased or decreased to increase or decrease the axial acting force transmitted from the command piston 20 to the nozzle needle 8, thereby stopping or starting the fuel injection by the injection nozzle 2.

  The hole region on the tip side of the sliding clearance 23 forms a low-pressure chamber 15 into which fuel leaked from the control chamber 19 flows via the sliding clearance 23, and the low-pressure chamber 15 includes a sliding clearance 13. Fuel also leaks from the high-pressure channel 12 on the injection nozzle 2 side.

  The main body 21 is provided with a low pressure passage 25 for collecting the fuel in the low pressure chamber 15 and returning it to the fuel tank. Here, the main body 21 is composed of a tip packing 26 that forms the tip of the main body 21 and a main body 27 other than the tip packing 26, and the low-pressure channel 25 is provided in the main body 27, and the low-pressure chamber 15 is formed across the chip packing 26 and the main body 27.

  The low pressure passage 25 and the low pressure chamber 15 communicate with each other via a groove 28 provided on the front end surface of the main body 27, and the fuel in the low pressure chamber 15 flows into the low pressure passage 25 via the groove 28. . The low-pressure chamber 15 accommodates a spring 29 that biases the nozzle needle 8 toward the closing side.

  A pressure pin 30 is disposed between the command piston 20 and the nozzle needle 8, and the fuel pressure in the control chamber 19 is transmitted from the command piston 20 to the nozzle needle 8 via the pressure pin 30. The pressure pin 30 is housed in the low pressure chamber 15 together with the spring 29. The pressure pin 30 has a seat for a spring 29, and the spring 29 urges the nozzle needle 8 toward the closing side via the pressure pin 30.

  The main body 27 has a hole opening surface 32 that opens at the rear end of the accommodation hole 22, and the control chamber 19 is formed by a plate-like member 33 that press-contacts the hole opening surface 32 so as to cover the opening of the accommodation hole 22. Blocked. Here, the control chamber 19 is connected to a control chamber inflow passage 34 for allowing fuel to flow into the control chamber 19 and a control chamber outflow passage 35 for allowing fuel to flow out from the control chamber 19. The path 35 is opened and closed with respect to the control chamber 19 according to the operation of the electromagnetic actuator 4.

  Each of the control chamber inflow passage 34 and the control chamber outflow passage 35 is provided with in and out orifices 36 and 37. The in and out orifices 36 and 37 are connected to the control chamber 19 with respect to the control chamber outflow passage 35. When opened, the fuel outflow rate from the control chamber 19 to the control chamber outflow channel 35 is set to be larger than the fuel inflow rate into the control chamber 19 through the control chamber inflow channel 34. .

The plate-like member 33 is provided with holes and holes corresponding to a part of the control chamber 19, a part of the control chamber inflow passage 34, and the in and out orifices 36 and 37. The plate member 33 communicates with the control chamber 19 on the plate member 33 side and the control chamber 19 on the main body 3 side, or the control chamber inflow passage 34 on the plate member 33 side and the control chamber inflow passage on the main body 3 side. It is press-contacted to the hole opening surface 32 so that it may communicate with 34.
The control chamber inflow passage 34 is branched from the main high-pressure passage 12 that guides the high-pressure fuel received from the common rail to the injection nozzle 2, and is a part of the high-pressure passage 12.

  The electromagnetic actuator 4 has an armature 40 and a stator 41 that form a magnetic circuit by energizing the solenoid coil 39, and holds the valve body 43 at the tip of a sliding shaft portion 42 that is integrated with the armature 40. The armature 40 is urged in a direction away from the stator 41 by a spring 44, and the sliding shaft portion 42 is supported by a valve body 45 so as to be slidable in the axial direction.

  Here, a hole provided in the valve body 45, a space on the outer peripheral side of the plate-like member 33, and the like form the control chamber outflow passage 35. Further, the low-pressure channel 25 opens to the hole opening surface 32 and is connected to the outer peripheral side space of the plate-like member 33 so as to communicate with the control chamber outflow channel 35, and the valve body 43 communicates with the control chamber outflow channel 35. Open and close with respect to the control room 19.

  As a result, when energization of the solenoid coil 39 is started, the armature 40 is attracted and moved toward the stator 41, the valve body 43 is moved to the rear end side in the axial direction, and the control chamber outflow path 35 is moved to the control chamber 19. On the other hand, it is released. When energization of the solenoid coil 39 is stopped, the armature 40 moves in a direction away from the stator 41 and the valve element 43 moves in the axial direction, and the control chamber outflow passage 35 is closed with respect to the control chamber 19. Is done.

  With the above configuration, when the electromagnetic actuator 4 operates by starting energization of the solenoid coil 39, the fuel pressure in the control chamber 19 decreases and the resultant force acting in the axial direction on the nozzle needle 8 increases to the open side. The needle 8 moves to the open side to open the space between the nozzle hole 6 and the distal end side flow path 14, and fuel injection starts.

  Further, when the operation of the electromagnetic actuator 4 is stopped by stopping the energization of the solenoid coil 39, the fuel pressure in the control chamber 19 rises and the resultant force acting in the axial direction on the nozzle needle 8 increases toward the closing side. 8 moves to the closed side, the space between the nozzle hole 6 and the front end side flow path 14 is closed, and fuel injection stops.

[Features of Example 1]
The features of the injector 1 according to the first embodiment will be described with reference to FIGS. 1 and 2.
First, around the sliding clearance 13, three high-pressure introduction passages 47 a, 47 b, 47 c for introducing high-pressure fuel are provided separately from the side passage 10. That is, as shown in FIG. 2, the nozzle body 7 is provided with high-pressure introduction passages 47a to 47c separately from the side passage 10, and the high-pressure introduction passages 47a to 47c are connected to the bag portion 14a and open. For this reason, the high pressure introduction passages 47a to 47c and the side passage 10 communicate with each other via the bag portion 14a, and the fuel pressure introduced into all of the side passage 10 and the high pressure introduction passages 47a to 47c is made uniform. Is done.

  Here, the side passage 10 and the high-pressure introduction passages 47 a to 47 c are linearly provided at equal angular intervals of 90 ° around the axis of the nozzle body 7 (hole axis of the accommodation hole 9). The side passage 10 is provided so that the flow path axis is included in the same plane as the hole axis of the accommodation hole 9, and the flow path axis intersects the hole axis of the accommodation hole 9. The introduction paths 47 a to 47 c are also provided in the same manner as the side path 10.

  The high-pressure introduction paths 47 a to 47 c open at the rear end of the nozzle body 7, and the opening at the rear end of the nozzle body 7 is sealed with the tip packing 26. Further, a positioning hole 48 is opened at the rear end of the nozzle body 7 in addition to the openings of the side passage 10 and the high-pressure introduction passages 47a to 47c.

[Effect of Example 1]
According to the injector 1 of the first embodiment, around the sliding clearance 13, three high-pressure introduction passages 47 a to 47 c through which high-pressure fuel is introduced are provided separately from the side passage 10.
As a result, a high-pressure flow region in which high-pressure fuel flows is formed on the outer peripheral side of the sliding clearance 13 as being divided into the side passage 10 and the high-pressure introduction passages 47a to 47c.

For this reason, since the sliding clearance 13 can be annularly surrounded by the high pressure flow region, the sliding surface on the nozzle body 7 side that forms the sliding clearance 13 is moved to the outer diameter side by the high fuel pressure in the high pressure flow region. Deformation can be suppressed.
As a result, in the injection nozzle 2 of the injector 1, the expansion of the sliding clearance 13 formed on the outer periphery of the nozzle needle 8 can be suppressed even if the fuel passing through the sliding clearance 13 is increased as the injection pressure is increased. Can do.

Further, the side passage 10 and the high pressure introduction passages 47a to 47c communicate with each other, and the fuel pressure introduced into each of the side passage 10 and the high pressure introduction passages 47a to 47c is made uniform.
As a result, the fuel pressure in the high-pressure flow region around the sliding clearance 13 can be made uniform in the circumferential direction, so variations in deformation suppression of the sliding surface on the nozzle body 7 side can be suppressed in the circumferential direction. .

The high-pressure introduction paths 47a to 47c are provided in a straight line and communicate with the side path 10 by opening to the bag portion 14a.
Thus, each of the high pressure introduction paths 47a to 47c can be provided, for example, by drilling with a single drill so that the side path 10 and each of the high pressure introduction paths 47a to 47c can communicate with each other. The process can be simplified.

[Example 2]
According to the injector 1 of the second embodiment, as shown in FIG. 3, an annular groove 50 is provided at the rear end of the nozzle body 7, and the groove 50 corresponds to each of the side passage 10 and the high-pressure introduction passages 47 a to 47 c. Intersects with the opening. Thereby, the side passage 10 and the high-pressure introduction passages 47a to 47c communicate with each other not only through the bag portion 14a but also through the groove 50.
For this reason, the fuel pressure in the high-pressure flow region around the sliding clearance 13 can be made more uniform in the circumferential direction.

[Modification]
The mode of the injector 1 is not limited to the first and second embodiments, and various modifications can be considered.
For example, according to the injector 1 of the first embodiment, the side passage 10 and the high-pressure introduction passages 47a to 47c communicate with each other via the bag portion 14a, and according to the injector 1 of the second embodiment, the side passage 10 and The high pressure introduction paths 47a to 47c communicated with each other through the bag portion 14a and the groove 50. However, the communication between the side path 10 and the high pressure introduction paths 47a to 47c is not limited to such an embodiment. The side passage 10 and the high-pressure introduction passages 47a to 47c may be communicated only with the groove 50. Further, the groove 50 may be provided at the tip of the chip packing 26.
Moreover, according to the injector 1 of Example 1, 2, although the three high voltage | pressure introduction paths 47a-47c were provided, it is good also considering the setting number of high voltage | pressure introduction paths as 1, 2 or 4 or more.

DESCRIPTION OF SYMBOLS 1 Injector 2 Injection nozzle 3 Main body 6 Injection hole 7 Nozzle body 8 Nozzle needle 9 Accommodating hole 10 Side passage 12 High pressure flow path 13 Sliding clearance 14 Front end side flow path 14a Bag part 47a-47c High pressure introduction path 50 Groove

Claims (4)

Injector comprising: an injection nozzle for injecting high-pressure fuel; and a main body for receiving high-pressure fuel from a fuel supply source, the injector being configured by fastening the injection nozzle to the front end side in the axial direction of the main body.
The injection nozzle has a nozzle body having a nozzle hole at the tip, and a nozzle needle that is accommodated in the nozzle body and is slidably supported in the axial direction,
The nozzle body includes an accommodation hole that supports and accommodates the nozzle needle so as to be slidable in the axial direction, and a side opening that is connected to the accommodation hole from the side and opens at the rear end of the nozzle body. The nozzle hole has an opening at the tip of the receiving hole,
The injection nozzle is fastened to the main body such that a main body side high-pressure channel for guiding high-pressure fuel in the main body and the side path communicate with each other, and the high-pressure fuel is supplied from the main body to the accommodation hole through the side path. Accept,
The nozzle body and the nozzle needle constitute a sliding support structure of the nozzle needle on the rear end side of the receiving hole from the position where the side path opens, and form a sliding clearance. Forming a tip-side flow path that guides high-pressure fuel to the nozzle hole on the tip side of the dynamic clearance;
The nozzle needle moves in the axial direction to start or stop fuel injection by opening and closing between the tip side flow path and the injection hole,
An injector having a high-pressure introduction path through which high-pressure fuel is introduced separately from the side path, around the sliding clearance. The injector according to claim 1, wherein
The injector is characterized in that the side passage and the high-pressure introduction passage communicate with each other, and the fuel pressure introduced into each of the side passage and the high-pressure introduction passage is made uniform. Injector according to claim 2,
The distal end side flow path is provided with a bag portion that expands in the radial direction, and the side path is connected to the bag portion and opened,
The injector is characterized in that the high-pressure introduction path communicates with the side path by opening in the bag portion. In the injector according to any one of claims 1 to 3,
The high-pressure introduction path opens at the rear end of the nozzle body,
The injector is characterized in that the side passage and the high-pressure introduction passage communicate with each other through a groove provided at a rear end of the nozzle body.

Images