JP5891094B2 - Fuel delivery pipe with damper function - Google Patents

Description

  The present invention relates to a fuel delivery pipe for use in supplying fuel to an electronically controlled fuel injection engine.

  In this type of fuel delivery pipe, for example, as disclosed in Patent Document 1 below, an upper case (upper divided body) and a lower case (lower divided body) formed by pressing are integrally joined to form a lower portion. In some cases, a plurality of sockets (injector insertion recesses) to which a fuel injection valve (injector) is connected to a case are formed at a predetermined interval. This fuel delivery pipe is used by connecting a plurality of sockets provided in the lower case to each fuel injection valve of a multi-cylinder engine in a liquid-tight manner, and is supplied from the fuel pump through the fuel supply pipe into the fuel delivery pipe. The fuel of a predetermined pressure is supplied to the engine in an optimum amount according to the operating conditions by controlling the opening and closing of each fuel injection valve by the control unit. In such a fuel piping system including a fuel delivery pipe, the fuel pressure inside the fuel delivery pipe pulsates with the periodic opening and closing of each fuel injection valve, causing variations in the fuel injection amount and keeping the air-fuel ratio within the target range. There is a problem that it becomes impossible to keep it. However, this problem is that the thickness of each plate part of the fuel delivery pipe is reduced and each wall surface is easily displaced in the plate thickness direction with respect to the pulsating fuel pressure, and the volume of the internal space is easily changed to cause pressure pulsation. It can be solved by mitigating. In addition, if the plane part of the ceiling wall of the upper case is inclined to increase the area of the plane part, the wall surface is more easily displaced in the plate thickness direction, and if the inclined plane part is a concave curved wall or a concave bent wall, Since the area of the wall surface is further expanded, the wall surface is further easily displaced, and it is possible to further reduce the pressure pulsation.

In Cited Document 1, since the plate thickness and shape are set so that the period of the resonance frequency of the fuel delivery pipe is less than the period of the idling rotational speed, no resonance phenomenon occurs. The amplitude of the internal pressure pulsation is not amplified. This also reduces the variation in the fuel injection amount due to the pulsation of the fuel pressure, so that the air-fuel ratio can be kept within the target range.
Japanese Patent No. 3538798 (see paragraph [0005], paragraph [0011], paragraph [0031], FIG. 3 and FIG. 4).

  This type of fuel delivery pipe may be provided with a sensor that detects the fuel pressure inside the fuel delivery pipe, but the plug for mounting such a sensor is liquid-tightly attached to one end face of the fuel delivery pipe. It was normal to do. However, there are cases where it is desired to attach this plug to the upper surface of the fuel delivery pipe for reasons of mountability. In such a case, for example, comparative examples having structures as shown in FIGS. 5 to 8 show only the right half for the sake of scale reduction, the left half is substantially the same as the embodiment of the present invention described later with reference to FIGS.

  The fuel delivery pipe of the comparative example shown in FIGS. 5 to 8 includes an upper case 2 in which a plug 3 for attaching a pressure sensor is liquid-tightly fixed on the upper surface, and a lower case 4 in which a plurality of sockets 5 and a bracket 6 are fixed. It is configured. The upper case 2 is integrated with an outer peripheral wall 2a composed of a front wall 2a1, a rear wall 2a2, left and right end walls (only the right end wall 2a3 is shown), and an upper edge of the outer peripheral wall 2a via each convex curved wall. It consists of a ceiling wall 2b that is connected to each other and closes the upper side thereof, and has an elongated box shape with the lower side opened. 5 and 6, in the range excluding the right end portion of the upper case 2, the height of the front wall 2a1 is larger than the height of the rear wall 2a2, as shown in FIG. 7, and the ceiling wall 2b in this range is shown in FIG. As shown in FIG. 2, the front wall 2a1 side is high and the rear wall 2a2 side is low. The inclined wall 2d is a concave curved wall, and is inclined wall at most positions excluding the recessed portion formed along the longitudinal direction in a part of the rear wall 2a2 of the fuel delivery pipe 1 as shown in FIG. The hem portion of 2d is smoothly connected to the horizontal base plane wall 2c. As shown in FIG. 6, the base plane wall 2c extends to the right end of the upper case 2, while the inclined wall 2d is interrupted just before the right end of the fuel delivery pipe 1 and is raised by the rising wall 2e. It is connected to. As a result, the right end portion of the base plane wall 2c is a tip portion 2c1 bent downward in FIG. 5, and the plug 3 is fixed on the tip portion 2c1. The lateral width of the distal end portion 2c1 is the smallest dimension to which the plug 3 can be fixed or slightly larger than that, and the longitudinal width of the distal end portion 2c1 is larger than that.

  The lower case 4 includes a bottom wall 4a and an outer peripheral flange 4b that rises from the four sides thereof, and four sockets 5 (only two are shown in FIG. 6) to which a fuel injection valve is connected to the lower surface of the bottom wall 4a. Two brackets 6 (only one is shown in FIG. 6) having mounting holes 6a are fixed. The outer surface of the outer peripheral flange 4b of the lower case 4 is fitted and inserted into the inner surface of the outer peripheral wall 2a of the upper case 2, and is fixed in a liquid-tight manner by brazing.

  In the fuel delivery pipe 1 of the comparative example shown in FIGS. 5 to 8, the area of the inclined wall 2 d that contributes most to the relief of the pressure pulsation inside is reduced by the width of the tip 2 c 1 of the basic planar wall 2 c, so that the pressure Although the pulsation mitigating function is reduced, the tip 2c1 to which the plug 3 is fixed increases the area of the flat base plane wall 2c, and the reduction is almost recovered. The tip portion 2c1 and a part of the base plane wall 2c that follows the tip portion 2c1 are continuously flat and become a wide plane, and the deflection due to the pressure pulsation in the fuel delivery pipe 1 is increased. Stress concentration occurs. Therefore, if the plug 3 is fixed to the tip portion 2c1 of the base flat wall 2c of the upper case 2 by brazing or resistance welding, sufficient fatigue strength cannot be secured, and welding is performed using a welding rod such as TIG welding or MIG welding. Since the fixing is required, there is a problem that the manufacturing cost increases. Recently, the above problem has become important because the pressure of the fuel supply system tends to increase in order to improve the fuel consumption rate and cope with alcohol fuel. The present invention aims to solve such problems.

In order to achieve this object, the fuel delivery pipe having the damper function according to claim 1 is provided with a plurality of sockets (35) on the bottom wall to which the fuel injection valves controlled and controlled by the control unit are connected. The lower case (30) having an open upper side and an outer peripheral wall (21) composed of a front wall, a rear wall, and left and right end walls, and the convex curved walls (22a, 22b). The upper case includes an upper case (20) which is integrally connected to the upper edge of the outer peripheral wall and has a ceiling wall (22) which closes the upper side thereof and is open on the lower side. A space (A) filled with a predetermined pressure of fuel supplied from a fuel pump is formed between the lower case and the lower case, and the space is formed by opening and closing the fuel injection valve. Pulsation of fuel pressure inside Accordingly, at least a part of the wall surfaces of both cases (30, 20) is bent to change the volume of the space, thereby reducing the pulsation of the fuel pressure in the space, and a fuel delivery having a damper function. In the pipe
In most of the upper case except for at least one end in the longitudinal direction of the ceiling wall, an inclined wall (24) is formed in which the front wall side is high and the rear wall side is low. A ridge line (R) extending along the longitudinal direction is formed by the highest portion of the convex curved wall (22a) connecting the two, and one of the left and right end walls is located on the one end side. age,
By curving the inclined wall toward the rear wall before the one end, the shoreline is branched into a portion extending straight to the one end and a portion separating from the rear wall. A top flat wall (25) having the same height as the shoreline is formed on the ceiling wall between both portions and the one end, and the one end wall side and the front wall side of the top flat wall are formed. The vertical width (W) in the direction perpendicular to the longitudinal direction of the upper case is narrower than the distance between the front wall and the rear wall of the upper case and detects the fuel pressure in the space. An intermediate plane wall (26) having a minimum width required for fixing the sensor mounting plug (28) or slightly larger than that is formed at a position one step below the top plane wall (25). Each end edge on the front wall side and the one end wall side of the plane wall is It is connected to the front wall and the one end wall via the convex curved walls (22a, 22b), and is opposite to the front wall and the one end wall of the intermediate plane wall (26). Each edge and the top plane wall are connected to the ceiling wall of the upper case via a substantially L-shaped rising wall (27) when viewed from above, and the plug (28) is connected to the intermediate plane wall (26). it is characterized in that it has solid wear.

The fuel delivery pipe having a damper function according to claim 1, wherein a width (W1) of the intermediate plane wall (26) in a direction orthogonal to the vertical width direction is also the same as the vertical width (W). preferable.

The fuel delivery pipe having a damper function according to claim 1 or 2, wherein the inclined wall (24) is preferably a concave curved wall or a concave bent wall.

A fuel delivery pipe having a damper function according to any one of claim 1 to 3 in the plug (28) threaded hole (28a) is in communication with the space (A) in the fuel delivery pipe It is preferable to be formed through the same axis.

Oite to the invention of claim 1, wherein the upper case of the ceiling wall of the longitudinal said front wall side is high the rear wall side for most except at least one end portion in the direction is lower inclined wall (24) while being formed, the ridge lines extending in the longitudinal direction by the highest portion of the inclined wall and the convex curved wall connecting said front wall (22a) (R) is formed, said one of said left and right end walls end and one end wall what lies side, extends straight the inclined wall in front at the one end portion side of the ridge line by bending the rear wall side of said one end portion of the and is branched into a portion away to the rear wall side therefrom the two portions and said to be between one end the top wall to the ridge line at the same height as the top plane wall (25) is formed, the top portion the corner portion serving as said one end wall and the front wall side of the planar walls, before Serial plug for sensor mounting longitudinal direction perpendicular to the direction of longitudinal width of the upper case (W) is to detect the fuel pressure in the narrow and the space than the distance between the front and rear walls of the upper case (28 ) minimum needed to secure the width or more somewhat larger degree of intermediate planar wall (26) is formed on one step lower position than the top planar walls (25), the front wall side of the intermediate planar walls and each edge is the respective convex curved walls (22a, 22b) serving as the one end wall while being connected to said front wall and said one end wall through said of the intermediate planar walls (26) front wall and said the other end wall and the end edge on the opposite side said top planar wall is connected to a ceiling wall of the upper case through a substantially L-shaped rising wall (27) when viewed from above, the The plug (28) is fixed to the intermediate plane wall (26). .

  According to the first aspect of the present invention, the intermediate flat wall to which the plug having high rigidity is fixed is the minimum width necessary for fixing the plug or the vertical width in the direction perpendicular to the longitudinal direction of the upper case. It is somewhat larger, and the portion outside the plug is small, so that the rigidity is high, and the two outer peripheral edges of the intermediate plane wall that is one step lower than the top plane wall are connected to the front wall of the upper case through the convex curved walls and Since one end wall is integrally connected and reinforced, and the remaining two outer peripheral edges are also reinforced by connecting the top flat wall of the upper case via a substantially L-shaped rising wall when viewed from above, The rigidity becomes extremely large. Therefore, the bending of the intermediate plane wall due to the pressure pulsation in the fuel delivery pipe is small, and the stress concentration generated in the vicinity of the fixed part with the plug is also small, so welding using a welding rod such as TIG welding or MIG welding is not possible. It becomes unnecessary, and the necessary strength can be obtained by brazing or resistance welding. Therefore, the manufacturing cost can be reduced.

  Further, in the fuel delivery pipe having the damper function according to the invention of the first aspect, it is an inclined wall having a large area that contributes most to the relief of the pressure pulsation therein. The intermediate flat wall on which the plug is provided is formed on one end side of the upper case and close to the front wall side, whereas the inclined wall provided on the front wall side is formed on one end portion of the upper case. Since the front wall is curved toward the rear wall to avoid interference with the intermediate plane wall, the length of the inclined wall extending in the longitudinal direction is reduced. Accordingly, the contribution to the relief of pressure pulsation due to the inclined wall due to the provision of the intermediate plane wall and the plug is small.

  In the fuel delivery pipe having the damper function according to the previous item, the width of the intermediate plane wall in the direction perpendicular to the vertical width direction is also the same as the vertical width. The minimum width required to secure the plug is slightly larger than the minimum width, the portion outside the plug is smaller, and the rigidity of the intermediate plane wall is higher. Therefore, the deflection of the intermediate plane wall due to the pressure pulsation in the fuel delivery pipe is further reduced, and the stress concentration generated in the intermediate plane wall in the vicinity of the fixed portion with the plug is also reduced, so that the necessary strength can be obtained by brazing or resistance welding. Manufacturing costs can be reduced.

  In the fuel delivery pipe having the damper function according to the preceding item 2, the inclined wall is a concave curved wall or a concave bent wall. According to the invention of claim 3, the length of the inclined wall in the direction orthogonal to the longitudinal direction is Since the pressure increases, the pressure receiving area increases, and the displacement of the volume of the fuel delivery pipe 10 with respect to the pulsating fuel pressure can be increased. As a result, the pressure pulsation in the fuel delivery pipe is further alleviated, and the stress generated in the intermediate plane wall near the fixing portion with the plug is further reduced.

According to the invention of claim 4 , in the fuel delivery pipe having the damper function described in the preceding item 3 , the plug is formed with a screw hole communicating with the space in the fuel delivery pipe coaxially therethrough. Since the internal structure of the plug is simplified and the outer diameter thereof can be reduced, the scope of application of the present invention when the front and rear width of the fuel delivery pipe is small can be expanded.

It is a top view which shows the whole structure of one Embodiment of the fuel delivery pipe provided with the damper function by this invention. It is a front view of embodiment shown in FIG. FIG. 3 is a sectional view taken along line 3-3 in FIG. 2. FIG. 4 is a sectional view taken along the line 4-4 in FIG. It is a top view which shows the whole structure of the comparative example of the fuel delivery pipe provided with the damper function. It is a front view of the comparative example shown in FIG. It is 7-7 sectional drawing of FIG. It is 8-8 sectional drawing of FIG.

  Hereinafter, a fuel delivery pipe having a damper function according to the present invention will be described based on the embodiment shown in FIGS. As shown in FIGS. 1 and 2, the fuel delivery pipe 10 of this embodiment includes an upper case 20 that is elongated in the lateral direction and opened on the lower side, and a lower case 30 that is elongated in the lateral direction and opened on the upper side. Plug 28 for mounting a fuel pressure detection sensor, fuel supply pipe 29 to which pressurized fuel from a pump is supplied, four sockets 35 to which a fuel injection valve is connected, and two for mounting The bracket 36 is used. Each member 20, 28, 29, 30, 35, 36 is made of steel, is nickel-plated for rust prevention, and is integrally fixed liquid-tightly by brazing with a copper braze or the like. . As shown in the plan view of FIG. 1, the front surface of the fuel delivery pipe 10 is a single flat surface, but the rear surface has three concave portions 21b1 formed in front and rear of the portion on the right side of the rightmost concave portion 21b1. The width is the maximum.

  The upper case 20 extends in the left-right direction in FIGS. 1 and 2, and includes an outer peripheral wall 21 including a front wall 21a, a rear wall 21b, and left and right end walls 21c, 21d, and convex curved walls 22a to 22d formed around the upper case 20. And a ceiling wall 22 that is integrally connected to the upper edge of the outer peripheral wall 21 and closes the upper side thereof, and is formed into an elongated box shape with the lower side open, and is integrally formed by pressing. Of the left and right end walls 21c and 21d, the one end wall 21c is located on the one end E side which is the right side of the upper case 20 in FIGS. As shown in FIGS. 3 and 4, the lower edge 20a of the outer peripheral wall 21 of the upper case 20 is curved outward, and the portion outside the middle of the curve is removed by trimming. In addition, a plurality of inward positions for positioning the lower case 30 with respect to the upper case 20 by contacting the upper edge of the outer peripheral flange 32 of the lower case 30 described below at a position above the lower edge 20a of the outer peripheral wall 21 by a predetermined distance. A protrusion 21e is formed.

  As shown in FIG. 3, the upper case 20 has a height of the front wall 21a larger than the height of the rear wall 21b, and the ceiling wall 22 is located on the side of the front wall 21a. It is formed in the inclined wall 24 which becomes high at the rear wall 21b side. The inclined wall 24 is a concave curved wall having a large curvature radius in a cross section orthogonal to the longitudinal direction of the upper case 20, and the front edge thereof is integrally connected to the front wall 21a via the convex curved wall 22a. . The rear edge of the inclined concave curved wall 24 is connected to the rear wall 21b through the bottom flat wall 23 and the convex curved wall 22b that are gently continuous as long as the concave portion 21b1 is not formed in the rear wall 21b. . In the range where the concave portion 21b1 is formed in the rear wall 21b, the rear edge of the concave curved wall 24 is connected to the rear wall 21b via the convex curved wall 22b without going through the bottom flat wall 23. It should be noted that the concave curved wall 24 is not curved into one circular arc having a large curvature radius as shown in the figure, but the intersection of two flat plates bent at a large angle is projected to be smaller than the curvature radius of the concave curved wall 24. It may be replaced with a loose concave bent wall 24 connected by a curved wall. A ridge line R extending along the longitudinal direction is formed at the highest portion of the convex curved wall 22a connecting the front wall 21a and the concave curved wall 24.

  In the plan view shown in FIG. 1, the concave curved wall 24 formed close to the front wall 21a side is in front of one end E on the right side of the upper case 20, and on the rear wall 21b side as indicated by reference numeral 24a. Thus, the shoreline R of the ceiling wall 22 is branched into a portion Ra that extends straight to one end E side of the upper case 20 and a portion Rb that is separated from the rear wall 21b. The rear portion 22a2 of the convex curved wall 22a connecting the front wall 21a and the concave curved wall 24 is curved toward the rear wall 21b together with the branched portion Rb. A top flat wall 25 having the same height as the ridge line R is formed on the ceiling wall 22 between one end E of the case 20.

  An intermediate flat wall 26 is formed on the top flat wall 25 at a position lowered by one step at a corner portion on the one end wall 21c side and the front wall 21a side of the upper case 20 on the right side in FIGS. ing. The intermediate flat wall 26 has a vertical width w in a direction orthogonal to the longitudinal direction of the upper case 20 and a horizontal width w1 in a direction orthogonal thereto, which is narrower than the distance between the front wall 21a and the rear wall 21b of the upper case 20. And the minimum width required to fix the plug 28 for attaching the fuel pressure sensor, or a little larger than that. The end edges of the intermediate flat wall 26 on the front wall 21a side and the one end wall 21c side are connected to the front wall 21a and the one end wall 21c via the convex curved walls 22a1 and 22c. Each end edge opposite to the front wall 21a and the one end wall 21c is connected to the top flat wall 25 via a substantially L-shaped rising wall 27 when viewed from above. The rising wall 27, the top flat wall 25, and the intermediate flat wall 26 are integrally connected through a convex curved wall 27a and a concave curved wall 27b having a small radius of curvature, respectively. A mounting hole 26 a for the plug 28 is provided in the center of the intermediate plane wall 26. Further, the vertical portion and the horizontal portion of the substantially L-shaped rising wall 27 are connected by an arc-shaped portion 27c concentric with the mounting hole 26a.

  By forming the intermediate plane wall 26, the width of the front end portion 25a on the right side of the top plane wall 25, that is, one end portion E side, is narrowed. In the illustrated embodiment, the distal end portion 25a has a certain width over the entire length and has the same height as the top flat wall 25, but the present invention is not limited to this, and at least a part of the distal end portion 25a. May have a width of 0, or may be slightly lower or higher than the top planar wall 25.

  The plug 28 for attaching the fuel pressure sensor has a short cylindrical shape, and a screw hole 28a is formed coaxially from the upper surface to the middle. Around the opening to the lower surface of the communication hole 28c extending downward from the bottom of the screw hole 28a. The cylindrical portion 28b is integrally formed. The plug 28 is positioned by fitting its cylindrical portion 28b into the mounting hole 26a of the intermediate flat wall 26 from above, and is fixed to the upper surface by brazing. The liquid-tight fixation of the plug 28 to the intermediate plane wall 26 is not limited to brazing, and an annular protrusion surrounding the cylindrical portion 28b is formed on either one of the contact surfaces of both, and resistance welding using this can be performed. Good.

  Further, in the plan view shown in FIG. 1, the shoreline R of the ceiling wall 22 is branched to the rear wall 21b side before the other end wall 21d on the left side of the upper case 20, and the rear wall 21b and the other end wall are branched. A substantially triangular second top plane wall 25b having a small triangle height approximately the same as the ridgeline R is formed on the ceiling wall 22 between the two walls 21d. A small slope wall 22e is formed between the second top plane wall 25b, the rear wall 21b, and the other end wall 21d, and an opening having an inward flange formed by burring in the small slope wall 22e ( One end portion of the fuel supply pipe 29 is inserted and fixed in a liquid-tight manner by brazing.

  Although the outer shape of the upper case 20 described above is complicated, its shape is flat (front and rear left and right front walls 21a to 21d, bottom flat wall 23, top flat wall 25, intermediate flat wall 26, etc.), cylindrical surface (convex curve). Wall 22a-22d, concave curved wall 24, etc.) and curved surfaces (spherical surface, decentered spherical surface, donut-shaped surface, part of other three-dimensional curved surfaces, symbols omitted) that smoothly connect these surfaces. The boundary line is indicated by a thin solid line. In FIGS. 3 and 4, portions corresponding to these boundary lines are shown with small black circles.

  Next, as shown in FIGS. 1 to 4, the lower case 30 is formed in a long and narrow box-like shape having a flat bottom wall 31 and an outer peripheral flange 32 having a constant height raised from the entire periphery thereof, the upper side being opened. It is an integrally molded product by press working. The front and left and right outer peripheral flanges 32 and the bottom wall 31 are integrally connected by a convex curved wall 31a having a small radius of curvature, and the rear side where the concave portion corresponding to the concave portion 21b1 of the rear wall 21b of the upper case 20 is formed. The outer peripheral flange 32 and the bottom wall 31 are integrally connected by a convex curved wall 31b having a large curvature radius. Four round mounting holes 33 for positioning and fixing the socket 35 are formed in the bottom wall 31 at the same interval. The outer peripheral flange 32 of the lower case 30 has an outer peripheral surface that can be fitted to the inner peripheral surface of the outer peripheral wall 21 of the upper case 20 with a slight gap.

  As shown mainly in FIG. 3, the socket 35 is an integrally molded product including a bottomed cylindrical main body portion 35 a and a cylindrical portion 35 b having a smaller diameter than the main body portion 35 a protruding outward from the bottom surface. In the socket 35, the cylindrical portion 35 b is inserted into the mounting holes 33 of the bottom wall 31 of the lower case 30 from below, the bottom surface of the main body portion 35 a is in contact with the lower surface of the bottom wall 31, and the liquid is applied to the lower case 30. Closely brazed and fixed. The inside of the main body portion 35a of the socket 35 thus fixed is formed between the lower case 30 and the upper case 20 covering the upper side thereof through an opening 35c formed by the inner surface of the cylindrical portion 35b. It communicates with the space A. Brackets 36 provided with attachment holes 36a are abutted and fixed to the lower surface of the bottom wall 31 of the lower case 30 that is located on the center side of the sockets 35 located on both outer sides.

  The upper case 20 covers the entire upper side of the lower case 30 by fitting and inserting the outer peripheral wall 21 formed with inward protrusions 21e at a plurality of lower portions to the outer side of the outer peripheral flange 32 of the lower case 30. An insertion position is determined by contacting the upper edge of the outer peripheral flange 32, and a space A in which fuel is filled is formed between the lower case 30 and a liquid-tight brazing and fixing.

  According to the embodiment as described above, the intermediate flat wall 26 to which the rigid plug 28 is fixed by brazing or resistance welding has the vertical width w in a direction perpendicular to the longitudinal direction of the upper case 20 to fix the plug 28. The minimum width necessary for the operation is slightly larger than that, and since there are few portions outside the plug 28, the rigidity is high, and the two outer peripheral edges of the intermediate flat wall 26 that is one step lower than the top flat wall 26 are convex. The front wall 21a and the one end wall 21c of the upper case 20 are integrally connected and reinforced through the curved walls 22a and 22c, and the remaining two outer peripheral edges also have a substantially L-shaped rising wall 27 as viewed from above. Since the top flat wall 25 of the upper case 20 is connected and reinforced, the rigidity is extremely increased. Therefore, the bending of the intermediate flat wall 26 in the thickness direction due to the pulsating fuel pressure in the fuel delivery pipe 10 is small even when the pressure of the fuel supply system is high. As a result, the stress concentration generated in the vicinity of the fixing portion with the plug 28 having a high rigidity is reduced, so that welding using a welding rod such as TIG welding or MIG welding is not required, and the necessary strength can be obtained by brazing or resistance welding. It is done. Therefore, the manufacturing cost can be reduced.

  In the fuel delivery pipe having such a damper function, the inclined wall 24 and the bottom flat wall 23 contribute most to the relief of the pressure pulsation inside the fuel delivery pipe. The flat wall 26 is formed close to the front wall 21a side on one end E side of the upper case 20, whereas the inclined wall 24 provided on the front wall 21a side is formed on the one end E side. The front wall is bent toward the rear wall 21b and is prevented from interfering with the intermediate plane wall 26, thereby reducing the extent to which the length of the inclined wall 24 is shortened and reducing the area reduction. Therefore, by providing the intermediate plane wall 26 and the plug 28, the decrease in the contribution to the relief of the pressure pulsation by the inclined wall 24 is small.

  In the above-described embodiment, the intermediate plane wall 26 has the same width w1 in the direction perpendicular to the vertical width w direction as the vertical width w. In this way, the horizontal width w1 of the intermediate plane wall 26 also fixes the plug 28. The minimum width necessary for this is slightly larger than that, and the portion outside the plug 28 is further reduced, so that the rigidity of the intermediate plane wall 26 is further increased. Therefore, the fluctuation of the thickness of the intermediate flat wall 26 in the thickness direction due to the pulsating fuel pressure in the fuel delivery pipe 10 is further reduced, and the stress concentration generated in the intermediate flat wall 26 near the fixing portion with the plug 28 is further reduced. . Therefore, the required strength can be obtained by brazing or resistance welding, and the manufacturing cost can be reduced.

  In the above-described embodiment, the inclined wall 24 is a concave curved wall, and in this way, the length of the inclined wall 24 in the direction orthogonal to the longitudinal direction of the upper case 20 increases, so the pressure receiving area increases, The displacement amount of the volume of the fuel delivery pipe 10 with respect to the pulsating fuel pressure can be increased. As a result, the pressure pulsation in the fuel delivery pipe is further alleviated, and the stress generated in the intermediate plane wall near the fixing portion with the plug having high rigidity is further reduced. Even when the inclined wall 24 is a concave bent wall, the length of the inclined wall 24 in the direction orthogonal to the longitudinal direction of the upper case 20 is increased and the pressure receiving area is increased.

  In the above-described embodiment, the tip end portion 25a on the one end E side of the top flat wall 25 is provided with a certain width over the entire length, but the present invention is not limited to this as described above. However, at least a part of the width may be zero, and in this case, the rising wall 27 that is located between the rear wall 21b of the upper case 20 and the plug 28 and reinforces the rigidity of the intermediate flat wall 26, and thereafter It is possible to reduce the front-rear width of the bulging portion due to the convex curved wall 27a, the distal end portion 25a of the top flat wall 25, and the convex curved wall 22b. In this way, the present invention can be applied even when the front-rear width of the fuel delivery pipe 10 is small or when the thick plug 28 is required.

  Further, in the above-described embodiment, the plug 28 is formed so as to pass through the screw hole 28a communicated with the space A coaxially, so that the internal structure of the plug 28 is simplified and the outer diameter thereof is increased. Therefore, the present invention can be applied even when the front and rear width of the fuel delivery pipe 10 is small.

DESCRIPTION OF SYMBOLS 20 ... Upper case, 21 ... Outer wall, 21a ... Front wall, 21b ... Rear wall, 21c ... One end wall, 21d ... End wall, 22 ... Ceiling wall, 22a-22d ... Convex curve wall, 24 ... Inclined wall ( (Concave curved wall, concave bent wall), 25 ... top flat wall, 25a ... tip, 26 ... intermediate flat wall, 27 ... rising wall, 28 ... plug, 28a ... screw hole, 30 ... lower case, 31 ... bottom wall, 35 ... Socket, A ... Space, E ... One end, R ... Round wire, Ra, Rb ... Part, w ... Vertical width, w1 ... Horizontal width.

Claims (4)

An elongated box-shaped lower case (30) having a plurality of sockets (35) connected to a fuel injection valve controlled by a control unit and provided on the bottom wall and open on the upper side;
An outer peripheral wall (21) composed of a front wall, a rear wall, and left and right end walls, and a ceiling wall integrally connected to the upper edge of the outer peripheral wall via each convex curved wall (22a, 22b) and closing the upper side thereof (22), comprising an elongated box-shaped upper case (20) whose lower side is open,
The upper case covers the upper side of the lower case and is brazed and fixed in a liquid-tight manner to form a space (A) filled with a predetermined pressure of fuel supplied from a fuel pump with the lower case,
The fuel in the space is changed by flexing at least part of the wall surfaces of the two cases (30, 20) according to the pulsation of the fuel pressure in the space due to the opening and closing of the fuel injection valve. In the fuel delivery pipe with a damper function to reduce the pressure pulsation,
In most of the upper case except for at least one end in the longitudinal direction of the ceiling wall, an inclined wall (24) is formed in which the front wall side is high and the rear wall side is low, and the inclined wall and the front wall are formed. A ridgeline (R) extending along the longitudinal direction is formed by the highest portion of the convex curved wall (22a) connecting the two,
One of the left and right end walls on the one end side is referred to as one end wall,
By curving the inclined wall toward the rear wall before the one end, the shoreline is branched into a portion extending straight to the one end and a portion separating from the rear wall. A top flat wall (25) having the same height as the shoreline is formed on the ceiling wall between both portions and the one end,
The vertical width (W) in the direction perpendicular to the longitudinal direction of the upper case is at the corners on the one end wall side and the front wall side of the top flat wall. An intermediate plane wall (26) that is narrower than or slightly larger than the minimum width required to secure the sensor mounting plug (28) that detects the fuel pressure in the space is narrower than the distance between Formed at a position one step lower than the plane wall (25), each edge of the intermediate plane wall on the front wall side and the one end wall side passes through the convex curved walls (22a, 22b). Each end edge and the top plane wall of the intermediate plane wall (26) opposite to the front wall and the one end wall are connected to the front wall and the one end wall, as viewed from above. It is connected to the ceiling wall of the upper case through an L-shaped rising wall (27). ,
Fuel delivery pipe having a damper function, characterized in that the plug (28) and said intermediate planar solid wear wall (26).
The fuel delivery pipe having a damper function according to claim 1, wherein a width (W1) of the intermediate plane wall (26) in a direction orthogonal to the vertical width direction is also the same as the vertical width (W). Fuel delivery pipe with a characteristic damper function. The fuel delivery pipe having a damper function according to claim 1 or 2, wherein the inclined wall (24) is a concave curved wall or a concave bent wall. The fuel delivery pipe having a damper function according to any one of claims 1 to 3 , wherein a screw hole (28a) communicating with the space (A) penetrates the plug (28) coaxially. A fuel delivery pipe with a damper function.

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