JP2005207324A - High pressure fuel accumulator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure reliability of an intersection of an inner passage hole and a fuel passage hole where stress is easily concentrated due to raised fuel injection pressure. <P>SOLUTION: In the high pressure fuel accumulator provided with a common rail housing 7 and 8 including an inner passage hole 7a extending in the longitudinal direction and a fuel passage hole 15 connected to the inner passage hole 7a so that it intersects the direction along which the inner passage hole is formed, the high pressure fuel accumulator further includes guide portion 96 and 97 covering the periphery of an opening portion where the fuel passage hole 15 intersects the inner passage hole 7a, and protection member 9 having a connection hole 92 formed in the guide portion 96 and 97 for connecting the fuel passage hole 15 to the inner passage hole 7a, wherein the protection member 9 is formed of material with high mechanical strength comparing with the material for forming the common rail housing 7 and 8. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a high pressure fuel pressure accumulator, and is suitable for application to a high pressure fuel pressure accumulator used in, for example, a pressure accumulation type fuel injection device.

  2. Description of the Related Art Conventionally, an accumulator fuel injection device that accumulates high-pressure fuel in an accumulator called a common rail and supplies the accumulated high-pressure fuel to a diesel engine (hereinafter referred to as an engine) from an injector is known (Patent Document 1). reference). This type of accumulator is formed in the common rail housings 7 and 8 functioning as a kind of surge tank so as to extend in the longitudinal direction thereof, and is accumulated with an accumulator chamber 7a for temporarily accumulating high-pressure fuel. In order to distribute the high-pressure fuel to the injectors attached to the cylinders of the engine, a plurality of fuel passage holes 13 and 15 opened in the pressure accumulating chamber 7a are formed (see FIG. 10). As shown in FIG. 10, the fuel passage holes 13 and 15 are connected to the pressure accumulating chamber 7a extending in the longitudinal direction so as to intersect with each other.

The pressure accumulating chamber 7a is composed of an internal passage hole extending in the longitudinal direction, and the inner periphery of the internal passage hole is opened so that the fuel passage hole 13 intersects. The common rail housings 7 and 8 have a peripheral edge, that is, a crossing portion 14 of the opening.
JP-A-4-287866

  In the conventional accumulator, the fuel injection pressure of the fuel injected from the injector acts as an internal pressure on the inner periphery of the accumulator chamber 7a, and tensile stress is applied to the intersection 14 between the accumulator chamber 7a and the fuel passage holes 13 and 15 by the internal pressure. Is easy to concentrate. As the fuel injection pressure increases, the stress increases, which may affect the structural reliability. Therefore, there is a limit to increasing the fuel injection pressure, and it has been difficult to increase the fuel injection pressure.

  As a countermeasure, a method using a material having a high material strength for the base material of the common rail housing can be considered. However, in reality, a screw tightening portion for screwing and connecting the high-pressure fuel pipe is formed on the outer periphery of the common rail housing 8 surrounding the fuel passage hole, and the base material hardness is increased, so that the machinability is deteriorated. There is also a problem that delayed fracture of the screw tightening part occurs.

  The present invention has been made in view of such circumstances, and an object of the present invention is to ensure the reliability of the intersection between the internal passage hole and the fuel passage hole, where stress concentration is likely to occur by increasing the fuel injection pressure. .

  Another object is to provide a high-pressure fuel pressure accumulator that is easy to process while ensuring the reliability of the intersection between the internal passage hole and the fuel passage hole where stress is easily concentrated.

  According to claim 1 of the present invention, the high-pressure fuel accumulator comprising a common rail housing having an internal passage hole extending in the longitudinal direction and a fuel passage hole that intersects the forming direction of the internal passage hole and opens into the internal passage hole. A protective member having a guide portion that covers a peripheral edge of an opening where the fuel passage hole and the internal passage hole intersect, and a communication hole that is formed in the guide portion and that allows the fuel passage hole and the internal passage hole to communicate with each other. The protective member is formed of a material having higher mechanical strength than the material forming the common rail housing.

  According to this, the common rail housing is formed with an internal passage hole extending in the longitudinal direction and a fuel passage hole that intersects the forming direction of the internal passage hole and opens to the internal passage hole. The protective member is formed of a material having higher mechanical strength than the material forming the common rail housing, and has a guide portion that covers the periphery of the opening where the fuel passage hole and the internal passage hole intersect. As a result, the peripheral edge of the opening, that is, the intersecting portion is covered with a guide portion having a mechanical strength higher than that of the common rail housing, so that the intersecting portion can be protected by the guide portion against the internal pressure corresponding to the fuel injection pressure. Reliability can be ensured in response to higher pressures.

  According to claim 2 of the present invention, the guide part has a joint part joined to the fuel passage hole, and the joint part is fitted into the fuel passage hole.

  According to this, as a method of joining the guide portion to the fuel passage hole, since the guide portion has a joint portion that fits into the fuel passage hole, compared with a method of changing the base material of the common rail housing to a material having high material strength. The processability of the common rail housing in which the fuel passage hole is formed can be improved.

  According to claim 3 of the present invention, the guide portion has a flange portion extending from the fuel passage hole to the inner peripheral side of the internal passage hole.

  According to this, the guide part which covers the periphery of an opening part can have a collar part extended to the inner peripheral side of an internal passage hole from a fuel passage hole.

  According to claim 4 of the present invention, the communication hole has a throttling function to alleviate fuel pulsation generated in either the fuel stored in the internal passage hole or the fuel guided to the fuel passage hole.

  According to this, the communication hole formed in the guide portion and capable of communicating between the fuel passage hole and the internal passage hole causes fuel pulsation generated in either the fuel stored in the internal passage hole or the fuel guided to the fuel passage hole. It can have an aperture function that relaxes.

  According to claim 5 of the present invention, the communication hole has a hole diameter in which the pressure of the fuel stored in the internal passage hole and the pressure of the fuel guided to the fuel passage hole are substantially equal.

  According to this, the communication hole formed in the guide portion and capable of communicating the fuel passage hole and the internal passage hole has a hole diameter at which the fuel stored in the internal passage hole and the pressure of the fuel guided to the fuel passage hole are substantially equal. Can have.

  Hereinafter, embodiments in which the high-pressure fuel accumulator of the present invention is applied to a high-pressure fuel accumulator (hereinafter referred to as a common rail) of an accumulator fuel injection device will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a configuration diagram showing a high-pressure fuel accumulator according to this embodiment. FIG. 2 is an overall view showing an example of a schematic configuration of the high-pressure fuel accumulator according to the present embodiment. FIG. 3 is an overall system diagram of a pressure accumulation fuel injection device to which the present embodiment is applied. FIG. 4 is a cross-sectional view taken along section IV-IV in FIG. FIG. 5 is a cross-sectional view showing the protective member in FIG. FIG. 6 is a longitudinal sectional view showing an example of the processing method according to this embodiment.

  As shown in FIG. 3, the accumulator type fuel injection control device is a diesel engine (hereinafter referred to as an engine) of a multi-cylinder (for example, four cylinders in this embodiment of FIG. 1) mounted on a vehicle such as an automobile. Fuel is injected and supplied from an injector 5 attached to each cylinder to a combustion chamber (not shown) of the cylinder. As shown in FIG. 3, the accumulator fuel injection control device includes a common rail 1 according to the present invention and a high-pressure pump (hereinafter referred to as a supply pump) 3 that pressurizes and pumps fuel pumped from the fuel tank 2 to the common rail 1. And an injector 5 for injecting high-pressure fuel supplied from the common rail 1 through a high-pressure pipe (hereinafter, high-pressure fuel pipe) 4 into the cylinder of the engine. This accumulator fuel injection control device is operated by an electronic control device (hereinafter referred to as ECU) 6 as a control means, such as an engine operating state or operating condition, a vehicle driving state, and a driver's operation amount (will). Are detected through various sensors (not shown), and an optimal target injection amount, target injection timing, target injection period and target injection pressure are calculated by sensor signals from the various sensors, and an injector 5 and a supply pump 3 for controlling each of them. Etc. The ECU 6 includes a CPU for performing control processing and arithmetic processing, a storage device (memory such as ROM and RAM) for storing various programs and data, an input circuit, an output circuit, a power supply circuit, an injector drive circuit, and a pump drive circuit. A microcomputer having a well-known structure configured to include the above functions is provided.

  As shown in FIGS. 2 and 4, the common rail 1 includes an accumulator pipe portion 7 for accumulating high-pressure fuel, a pipe joint portion 8 for connecting the high-pressure fuel pipe 4, an accumulator pipe portion 7, and a pipe joint portion 8. It is comprised from the protection member 9 (refer FIG. 4) arrange | positioned inside.

  In addition, as shown in FIG. 2, the common rail 1 includes a pressure sensor 10 that detects the fuel pressure in the common rail 1 and outputs it to the ECU 6, and the fuel pressure in the common rail 1 does not exceed a preset upper limit value. A pre-limiter 11 that restricts to is attached. Specifically, as shown in FIG. 1, the pressure accumulating tube portion 7 is formed by an end face of the pressure sensor 10 and the pressure limiter 11 that oil-tightly seals the inner passage hole 7 a extending in the longitudinal direction and both ends of the inner passage hole 7 a. And a pressure accumulating chamber that is partitioned. The pressure accumulating chamber only needs to have an internal passage hole 7a extending in the longitudinal direction in the pressure accumulating tube portion 7 and both ends of the internal passage hole 7a are oil-tightly sealed. Further, the plug is not limited to the pressure limiter 11 and may be a blind plug or the like that seals both ends oil-tightly.

  The pipe joint portion 8 is formed separately or integrally with the pressure accumulating tube portion 7. As the material of the pressure accumulating pipe section 7 and the pipe joint section 8, carbon steel such as low carbon steel (for example, S45C) having relatively good cutting workability is used as a material. Inside the pipe joint 8, fuel passage holes 15 and 19 are formed so that the pipe joint 8 surrounds. The pipe joint portion 8 is formed with a screw tightening portion for screwing and connecting the high-pressure fuel pipe 4 to the outer periphery substantially concentric with the fuel passage holes 15 and 19. As shown in FIGS. 1 and 4, the screw tightening portion is formed with a male screw portion, and the high-pressure fuel pipe 4 has a female screw portion. The pipe joint portion 8 may have a female screw portion, and the high-pressure fuel pipe 4 may have a male screw portion.

  Here, the pressure accumulating pipe portion 7 and the pipe joint portion 8 constitute a common rail housing.

  In the following description of the present embodiment, it is assumed that the pressure accumulating pipe portion 7 and the pipe joint portion 8 are integrally formed.

  As shown in FIGS. 1 and 4, five fuel passage holes 15 and 19 (see FIG. 4) penetrating the inner periphery 18 (see FIG. 4) of the internal passage hole 7 a are provided. These fuel passage holes 15 are used as four fuel outlets connected to the injector via the high-pressure fuel pipe 4 and one fuel inlet connected to the supply pump 3 via the high-pressure fuel pipe 4, It arrange | positions at substantially equal intervals in the longitudinal direction of the pipe part 7 (specifically internal passage hole 7a). The fuel passage hole 15 is open to the internal passage hole 7a so as to intersect the forming direction of the internal passage hole 7a.

  Here, the periphery of the opening where the fuel passage holes 15, 19 (specifically, the fuel passage hole 15) and the internal passage hole 7a intersect is the intersection of the common rail housings 7, 8 (hereinafter referred to as the common rail housing intersection). Configure).

  As shown in FIG. 4, the protective member 9 is disposed in the fuel passage hole 15 and has guide portions 96 and 97 (see FIG. 5) that cover the intersection of the common rail housing. As shown in FIG. 5, the guide portions 96, 97 are a joint portion 97 that can be fitted into the fuel passage hole 19, and a flange that extends from the joint portion 97 to the inner periphery 18 (see FIG. 4) of the internal passage hole 7a. A portion 96 is included. The outer periphery 97 a of the joint 97 is fitted and fixed to the inner periphery of the fuel passage hole 19. The guide portions 96 and 97 are provided with a communication hole 92 that allows the internal passage hole 7a and the fuel passage hole 15 to communicate with each other. The communication hole 92 is formed to have a relatively small diameter compared to the fuel passage hole 15 (for example, the inner diameter of the fuel passage hole 15 is Φ3 mm, the inner diameter of the communication hole 92 is Φ0.6 mm), and the inner passage hole 7a (in detail) Is provided with a throttling function to alleviate fuel pulsation generated in either the fuel stored in the pressure accumulating chamber) or the fuel guided to the fuel passage hole 15.

  Specifically, the joint portion 97 is formed in a substantially cylindrical shape along the inner periphery 18 (see FIG. 4) of the internal passage hole 7a. The collar portion 96 is formed in a substantially square shape. As shown in FIG. 5, when the size of the outer periphery of the joint portion 97 is ΦD = Φ3 mm, the size of the substantially square of the flange portion 96 is preferably □ L = □ 5 mm or more. When these sizes are represented by a cross-sectional area, and the cross-sectional area S1 of the joint portion 97 and the cross-sectional area S2 of the flange portion, the ratio S2 / S1 is preferably S2 / S1 ≧ 3.5. The cross-sectional area S1 constitutes a cross-sectional area of a portion of the protective member 9 that is joined to the fuel passage hole 15. The cross-sectional area S2 constitutes the cross-sectional area of the portion of the protective member 9 that extends to the inner periphery 18 of the internal passage hole 7a.

  The material of the protective member 9 is a material having higher mechanical strength than the material forming the common rail housings 7 and 8 (for example, tool steel such as SCM, bearing steel, or steel material subjected to carburizing and quenching). .

  Of the guide portions 96, 97, the peripheral edge of the opening where the communicating hole 92 communicating with the internal passage hole 7a intersects the end surface of the flange portion 96 is an intersecting portion of the protection member 9 (hereinafter referred to as a protection member intersecting portion). ) 94.

  In the flange portion 96, the outer periphery 92a facing the inner periphery 18 of the internal passage hole 7a extends along the inner periphery 18, and has a shape that can be in close contact with the inner periphery 18 (specifically, the common rail intersection). Preferably it is formed.

  The protective member intersection 94 and the common rail intersection are chamfered as shown in FIG. Note that chamfering may not be performed.

  The manufacturing method of the present embodiment having the above-described configuration will be described with reference to FIG. As a method of fitting and fixing the protection member 9 to the fuel passage hole 19, the joint 97 of the protection member 9 is press-fitted into the fuel passage hole 19 as shown in FIG. 6. In detail, the press-fitting rod 100 thinner than the inner periphery 18 of the internal passage hole 7a is used as a press-fitting jig. As shown in FIG. 6, the press-fit rod 100 is provided with a groove for holding the protective member 9 corresponding to a predetermined interval of the fuel passage hole 19. The groove may be any groove that can position the protective member 9 at a predetermined interval. In addition, it is preferable that the protective member 9 can be temporarily fixed by the groove before press-fitting. As shown in FIG. 6, the protective member 9 can be temporarily fixed to the press-fit rod 100 even if it is positioned to the upper side of the press-fit rod 100 having grooves. Next, the protection member 9 is placed in the groove of the press-fit rod 100. The press-fitting rod 100 on which the protective member 9 is placed is inserted into the internal passage hole 7 a in the common rail housing 7, 8. The insertion position of the press-fitting rod 100 to be inserted is set so that the protective member 9 is disposed corresponding to the position of the fuel passage holes 15 and 19 (specifically, the fuel passage hole 19). At this time, since both ends of the common rail housings 7 and 8 are opened (penetrated) for processing the internal passage hole 7a, the press-fit rod 100 can be taken out from both ends of the common rail housings 7 and 8. As shown in FIG. 6, the protective member 9 can be press-fitted into the common rail housings 7, 8 by applying a load F to both ends of the press-fitting rods 100 protruding from the common rail housings 7, 8.

  The method of moving the protective member 9 to the fuel passage hole 19 is not limited to the method in which a groove for positioning is provided in the press-fit rod 100, and the protective member 9 is attached to a magnet or a magnetic iron rod by the magnetic force. Alternatively, the protection member 9 may be moved together with the iron bar, or the protection member 9 may be sucked and moved by air such as factory air.

  Next, the operation of the present embodiment having the above-described configuration will be described. When the engine key is set to the IG position and an ignition switch (not shown) is turned on, the injector 5 and the supply pump 3 are driven and controlled based on the control program stored in the memory of the ECU 6. When the supply pump 3 is driven, high pressure fuel of a predetermined discharge amount is supplied from the supply pump 3 through one fuel passage hole 15 into the pressure accumulating chamber. As a result, the fuel pressure in the pressure accumulating chamber (specifically, the internal passage hole 7a) of the common rail housings 7 and 8 is maintained at a level equal to or higher than a so-called common rail pressure corresponding to a predetermined fuel injection pressure. Then, high pressure fuel is supplied to each injector 5 through another fuel passage hole 15. When the injector 5 is driven and controlled to open, the pressure accumulating chamber, the high-pressure fuel pipe 4, and the high-pressure fuel in the injector 5 are injected and supplied into the combustion chamber of the engine.

  Here, when high-pressure fuel flows from the supply pump 3 into the internal passage hole 7a, the internal passage hole 7a and the fuel passage hole 15 in the common rail housings 7 and 8 and both ends of the protective member 9 (joints joined to the fuel passage hole 19). The common rail pressure acts as an internal pressure on the portion 97, the flange portion 96) extending to the inner periphery 18 of the internal passage hole 7a, and the communication hole 92. The protective member intersecting portion 94 of the protective member 9 is a portion where stress is easily concentrated by the internal pressure. However, since the mechanical strength is higher than the base material strength of the common rails 7 and 8, the influence of the internal pressure on the strain is small. Therefore, since the amount of distortion that deforms the common rail intersection covered by the protective member 9 can be reduced, the stress generated at the common rail intersection can be reduced.

  In addition, since the cross-sectional area ratio S2 / S1 of the both ends in the protection member 9 is secured to S2 / S1 ≧ 3.5, the flange 96 is pressed against the inner circumference 18 side of the internal passage hole 7a by the internal pressure. Thus, even if fuel pulsation occurs in either the fuel passage hole 15 or the fuel in the internal passage hole 7a, the common rail intersection can be reliably covered by the protection member 9 and the common rail intersection can be protected.

  In the prior art, as shown in FIG. 10, since the internal pressure directly acts on the common rail intersection 14, if the tensile stress due to the internal pressure acting on the inner periphery 18 of the internal passage hole 7 a is 1, the common rail intersection 14 The resulting tensile stress is concentrated to about 3 stresses. If the base material of the conventional common rail housings 7 and 8 is a low carbon steel such as S45C, an attempt to further increase the fuel injection pressure may lead to a decrease in structural strength and a problem that reliability is lowered. there were.

  Next, the operational effects of the present embodiment will be described. (1) The common rail housings 7 and 8 intersect the longitudinal direction of the internal passage hole 7a extending in the longitudinal direction and the internal passage hole 7a. The fuel passage holes 15 and 19 are formed to open at the bottom. The protective member 9 is made of a material having higher mechanical strength than the material forming the common rail housings 7 and 8, and the fuel passage holes 15 and 19 (specifically, the fuel passage hole 19) intersect with the internal passage hole 7a. Guide portions 96 and 97 that cover the periphery of the opening to be performed are provided. As a result, the peripheral edge of the opening, that is, the common rail intersection is covered with the guide portions 96 and 97 having higher mechanical strength than the common rail housings 7 and 8, so that the guide having high mechanical strength against the internal pressure corresponding to the fuel injection pressure. The amount of distortion at the common rail intersection can be reduced by the portions 96 and 97. As a result, since the stress generated at the common rail intersection can be suppressed to a low level, the common rail intersection can be protected, and reliability can be ensured in response to the increase in fuel injection pressure.

  Since the internal pressure directly acts on the protective member intersecting portion 94 of the protective member 9, the stress tends to be concentrated as compared with the inner periphery of the flange portion 96, but mechanically compared with the material forming the common rail housings 7 and 8. Since it is formed from a material having high strength, structural reliability is sufficiently ensured. Therefore, it is possible to cope with further increase in the fuel injection pressure.

  (2) As a method of joining the guide portions 96 and 97 to the fuel passage hole 19, since the guide portions 96 and 97 have the joint portion 97 that can be fitted to the fuel passage hole 19, the base material of the common rail housings 7 and 8 is used. Compared with a method of changing to a material having high strength, the workability of the common rail housings 7 and 8 can be improved.

  (3) In this embodiment, since it is not necessary to change the base material of the common rail housings 7 and 8 to a material having high material strength, reliability such as delayed fracture of the screw tightening portion formed in the pipe joint portion 8 is improved. There is no risk of problems.

  (4) Further, the guide portions 96 and 97 covering the periphery of the opening, that is, the intersection portion of the common rail housing, may have a flange portion 96 extending from the fuel passage holes 15 and 19 toward the inner periphery 18 side of the internal passage hole 7a. it can. Thereby, the collar part 96 can be latched to the inner periphery 18 of the internal passage hole 7a so that the protection member 9 does not move due to the common rail pressure in the internal passage hole 7a.

  It should be noted that the extension size of the flange 96 may be provided only in the range of the intersection where stress concentration is likely to occur.

  (5) A communication hole 92 formed in the guide portions 96 and 97 that allows the fuel passage hole 15 and the internal passage hole 7a to communicate with each other is provided for the fuel stored in the internal passage hole 7a and the fuel guided to the fuel passage hole 15 In the case of having a throttling function to alleviate the fuel pulsation occurring in any of the above, the cross-sectional area S1 of the portion of the protective member 9 that joins the fuel passage hole 19 and the cross-sectional area S2 of the portion that extends to the inner periphery 18 of the internal passage hole 7a The ratio S2 / S1 is preferably S2 / S1 ≧ 3.5. Thereby, in the load by the fuel pressure applied to the internal passage hole 7a side of the protective member 9 and the load by the fuel pressure applied to the fuel passage hole 15 side, it depends on the fuel pressure applied to the internal passage hole 7a side according to the ratio S2 / S1. Since the load, that is, the force that presses the protective member 9 against the inner periphery 18 of the internal passage hole 7a is superior, even if fuel pulsation occurs, the protective member 9 can reliably cover the intersection of the common rail housing. It is possible to prevent the protection member 9 from falling into the internal passage hole 7a due to a pressure difference between the internal passage hole 7a and the fuel passage hole 15.

  (6) In the present embodiment, a throttle function for reducing fuel pulsation in the fuel path in the common rail 1 as a method for stabilizing the common rail pressure in order to improve the fuel injection amount accuracy in response to exhaust gas and output improvement. When it is desired to provide the above-mentioned throttling function, the communication hole 92 of the protection member 9 can be provided with the above-described throttling function.

(Second Embodiment)
Hereinafter, other embodiments to which the present invention is applied will be described. In the following embodiments, the same or equivalent components as those in the first embodiment are denoted by the same reference numerals, and description thereof will not be repeated.

  In the first embodiment, the flange portion 96 of the protection member 9 is shaped so as to extend along the inner periphery 18 of the internal passage hole 7a. However, in the second embodiment, as shown in FIG. Then, the shape of the end face of the flange 196 that opens is a plane. FIG. 7 is a cross-sectional view showing a protective member according to this embodiment. The degree of stress concentration at the protection member intersection 194 is reduced according to the increase in curvature at the protection member intersection 194. Compared to the curved surface, the flat surface greatly enlarges the curvature of the protective member intersection 194. Therefore, stress concentration at the protection member intersection 194 is alleviated, so that the reliability of the protection member intersection 94, that is, the reliability of the common rail 1 can be improved. Compared with the first embodiment, the second embodiment can further improve the reliability of the intersection portion of the common rail housing between the internal passage hole 7a and the fuel passage holes 15 and 19 where the stress is easily concentrated by increasing the fuel injection pressure. It is.

  Note that the thickness of the collar 194 itself can be increased by changing the end surface of the collar 194 from a curved surface to a flat surface.

(Third embodiment)
In the third embodiment, as shown in FIG. 8, the pressure accumulating tube portion 7 of the common rail housings 7, 8 is formed by being substantially divided into half, and then applied to a so-called junction type common rail to be joined. FIG. 8 is a cross-sectional view showing a high-pressure fuel accumulator according to this embodiment.

  As shown in FIG. 8, the pressure accumulating pipe portion 7 is formed in a substantially half-divided manner, and a first pressure accumulating half pipe is obtained by substantially dividing the accumulating tube portion 7 into a first accumulating half tube 71 provided with a pipe joint portion 8. The second pressure accumulating half pipe 72 is the remaining part of 71. In the manufacturing process, the first pressure accumulation half pipe 71 and the second pressure accumulation half pipe 72 are separately formed. And the 1st pressure accumulation half pipe 71 and the 2nd pressure accumulation half pipe 72 are integrally welded by the annular contact surface. As the first pressure-accumulating half tube 71 and the second pressure-accumulating half tube 72 are welded together, the inner passage hole 118 is formed by the inner peripheries 71a and 72a of the first pressure-accumulating half tube 71 and the second pressure-accumulating half tube 72, respectively. It is formed. In addition, as long as the 1st pressure accumulation half pipe 71 and the 2nd pressure accumulation half pipe 72 can be joined integrally, not only welding but other joining methods, such as adhesion | attachment, may be sufficient.

  In the present embodiment, the manufacturing process of press-fitting the protective member 9 into the fuel passage hole 19 of the first pressure-accumulating half pipe 71 before the first pressure-accumulating half pipe 71 and the second pressure-accumulating half pipe 72 are joined together is configured. To do. As a result, the press-fitting target portion (specifically, the fuel passage hole 19) is not on the inner passage hole 118 but on the surface 71a of the inner periphery, so that the protective member 9 can be easily press-fitted. it can.

(Fourth embodiment)
In the fourth embodiment, as shown in FIG. 9, the hole diameter of the communication hole 292 is relatively larger than that of the communication hole 92 in the first embodiment. FIG. 9 is a cross-sectional view showing a protective member according to this embodiment. The communication hole 292 has a hole diameter at which the pressures of the fuel stored in the internal passage hole and the fuel guided to the fuel passage hole are substantially equal. Accordingly, in the communication hole 292 itself, the communication hole 92 that allows the fuel passage hole 15 and the internal passage hole 7 a to communicate with each other is generated in either the fuel stored in the internal passage hole 7 a or the fuel guided to the fuel passage hole 15. Does not have a throttling function to relieve fuel pulsation.

  A protective member intersecting portion 94 is formed on the curved surface of the flange portion 96 where the communication hole 92 intersects and opens.

  Thereby, since the protective member 9 does not produce a pressure difference between the internal passage hole 7a and the fuel passage hole 15, the degree of freedom in designing the cross-sectional area ratio S2 / S1 in the protective member 9 can be improved.

(Other embodiments)
In the present embodiment described above, the protective member 9 is set for each of the fuel passage holes 15 and 19. However, all of these protective members 9 may be integrated together.

It is a block diagram which shows the high pressure fuel accumulator of the 1st Embodiment of this invention. 1 is an overall view showing an example of a schematic configuration of a high pressure fuel accumulator according to a first embodiment. 1 is an overall system diagram of a pressure accumulation type fuel injection device to which a first embodiment is applied. It is the cross-sectional view seen from the cross section IV-IV in FIG. It is sectional drawing which shows the protection member in FIG. It is a longitudinal cross-sectional view which shows one Example of the processing method concerning 1st Embodiment. It is sectional drawing which shows the protection member concerning 2nd Embodiment. It is a cross-sectional view showing a high-pressure fuel accumulator according to a third embodiment. It is sectional drawing which shows the protection member concerning 4th Embodiment. It is a cross-sectional view showing a conventional high-pressure fuel accumulator.

Explanation of symbols

1 Common rail (high pressure fuel accumulator)
3 Supply pump (high pressure pump)
4 High-pressure fuel pipe (high-pressure piping)
5 Injector 7 Accumulator tube (part of common rail housing)
7a Internal passage hole 8 Piping joint (part of common rail housing)
9 Protective member 92 Communication part 96 collar part 97 joint part

Claims (5)

In the high-pressure fuel accumulator comprising a common rail housing having an internal passage hole extending in the longitudinal direction and a fuel passage hole that intersects the forming direction of the internal passage hole and opens into the internal passage hole,
A protection having a guide portion covering a peripheral edge of an opening where the fuel passage hole and the internal passage hole intersect, and a communication hole formed in the guide portion and capable of communicating the fuel passage hole and the internal passage hole. Comprising a member,
The high-pressure fuel accumulator is characterized in that the protective member is made of a material having a higher mechanical strength than the material forming the common rail housing. The guide part has a joint part joined to the fuel passage hole,
The high-pressure fuel accumulator according to claim 1, wherein the joint portion is fitted in the fuel passage hole. 3. The high-pressure fuel accumulator according to claim 1, wherein the guide portion has a flange portion that extends from the fuel passage hole to an inner peripheral side of the internal passage hole. 4. 4. The communication hole according to claim 1, wherein the communication hole has a throttling function to alleviate fuel pulsation generated in any of fuel stored in the internal passage hole and fuel guided to the fuel passage hole. The high-pressure fuel accumulator according to any one of the above. The said communicating hole has a hole diameter from which the pressure of the fuel stored in the said internal passage hole and the fuel guide | induced to the said fuel passage hole becomes substantially equal, The Claim 1 characterized by the above-mentioned. The high-pressure fuel accumulator described in 1.

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