Fuel delivery pipe

Abstract

To improve strength of a portion in which injection valve sockets and attachment brackets are disposed and a pulsation absorption function which absorbs pulsation of a fuel.SOLUTION: A fuel delivery pipe 10 includes: an upper case 20 having a pair of side wall parts 22 extending downward from both ends as seen in a width direction of an upper wall part 21 which extends with a direction from one side to the other side set to its longitudinal direction, the upper case 20 being open at both longitudinal ends and the lower side; a lower case 30 having at least a bottom wall part 31 which closes a lower side opening of the upper case 20 and covering the lower side of the upper case 20; plug members 41, 42 which are provided at openings 20a formed at both longitudinal ends of the upper and lower cases 20, 30 and close both longitudinal ends of a fuel passage 40 formed between the upper and lower cases 20, 30; multiple injection valve sockets 43 provided at the lower case 30; and attachment brackets 44 which are provided at the lower case 30 and used to attach the fuel delivery pipe 10 to an engine.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a fuel delivery pipe used when injecting fuel into the combustion chamber of a multi-cylinder engine. [Background technology]

[0002] Patent Documents 1 and 2 disclose fuel delivery pipes used to inject fuel into the combustion chambers of multi-cylinder engines. The fuel delivery pipe in Patent Document 1 includes a main pipe having a fuel passage formed therein through which fuel is supplied from a fuel pump, three injection valve sockets integrally formed with the main pipe and having injection valve insertion holes to which fuel injection valves are fluid-tightly connected, and two mounting brackets integrally formed with the main pipe for attaching the main pipe to the engine. In the fuel delivery pipe in Patent Document 1, the main pipe is made of a hollow, straight pipe material having a fuel passage formed therein through which fuel passes, and the fuel passage inside the main pipe is closed by covers attached to both longitudinal ends. The main pipe also has a substantially rectangular cross-section perpendicular to the longitudinal direction, and both side surfaces in the width direction perpendicular to the longitudinal direction serve as pulsation absorbing surfaces that absorb fuel pressure pulsations in the fuel passage.

[0003] The fuel delivery pipe of Patent Document 2 includes a lower case that is open at the top, an upper case that liquid-tightly covers the top of the lower case and forms an internal space between the lower case and the upper case that is filled with fuel at a predetermined pressure supplied from a fuel pump, three injection valve sockets that are integral with the lower case and have injection valve insertion holes to which fuel injection valves are connected, and two mounting brackets that are integral with the lower case and for mounting to an engine. In this fuel delivery pipe, part of the top surface of the upper case serves as a pulsation absorbing surface that absorbs pulsations of fuel pressure in the fuel passage. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-159302 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-197596 Summary of the Invention [Problem to be solved by the invention]

[0005] This type of fuel delivery pipe requires both increased strength in the area where the injection valve socket and mounting bracket are located and enhanced pulsation absorption capabilities for absorbing fuel pressure pulsations. In the fuel delivery pipe disclosed in Patent Document 1, the main pipe is made of a straight tubular material with a uniform circumferential thickness, and the fuel passage inside the main pipe is blocked by covers attached to both longitudinal ends. In this delivery pipe, the injection valve socket and mounting bracket are fixed to the lower part of the main pipe, so the main pipe must be thick to enhance its strength. However, if the main pipe is thickened, some of the sides of the main pipe will not be able to fully absorb the pulsation absorption capabilities. Thus, in a fuel delivery pipe in which the fuel passage is formed inside a straight tubular material with a uniform circumferential thickness, it has been difficult to achieve both increased strength in the area where the injection valve socket and mounting bracket are located and enhanced pulsation absorption capabilities for absorbing fuel pressure pulsations.

[0006] In addition, in the fuel delivery pipe of Patent Document 2, the lower case is constructed separately from the upper case, so by increasing the thickness of the lower case, the strength for arranging the injection valve socket and mounting bracket can be increased, and by reducing the thickness of the upper case, pulsation absorption function can be achieved through the pulsation absorbing surface. However, because the upper case has a generally box-like shape that opens downward to form an internal space filled with fuel between it and the lower case, the corners formed at the longitudinal ends of the upper case are thin-walled, which causes stress concentration, making it difficult to thin the thickness of the upper case enough to provide sufficient pulsation absorption function. The present invention aims to increase both the strength of the portion of the fuel delivery pipe where the injection valve socket and mounting bracket are arranged and the pulsation absorption function that absorbs fuel pulsations. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the present invention provides an upper case having an upper wall portion extending from one side to the other in the longitudinal direction and a pair of side wall portions extending downward from both widthwise ends of the upper wall portion, so that both longitudinal ends and the bottom side are open; and a bottom wall portion having a pair of side wall portions extending upward from both widthwise ends of a bottom wall portion that closes the lower opening of the upper case, so that both longitudinal ends and the top side are open. ,sideThe fuel injection valve sockets are provided in the lower case and have injection valve insertion holes to which fuel injection valves are fluid-tightly connected and communicate with the fuel passages; and a mounting bracket is provided in the lower case and used for mounting the engine. The fuel injection valve sockets and the mounting brackets are arranged in the lower case. and a fuel delivery pipe in which the thickness of the lower case is increased to increase the strength for delivering fuel to the fuel delivery pipe, and the thickness of the upper case is made thin so as to have a pulsation absorbing function, and protrusions are formed at both longitudinal ends of the upper case such that the lower ends of the side walls protrude to the bottom wall of the lower case, and curved crushed portions are formed at the corners between the bottom wall and the side wall at both longitudinal ends of the lower case, and inner plug members are fitted as plug members onto the inner peripheral surfaces of openings formed at both longitudinal ends of the upper and lower cases to close the openings formed at both longitudinal ends of the upper and lower cases.

[0008] In the fuel delivery pipe constructed as described above, the upper case is constructed separately from the lower case in which the injection valve socket and the mounting bracket are provided. The thickness of the lower case is increased to increase the strength for arranging the injection valve socket and the mounting bracket, and the thickness of the upper case is made thin so that it has a pulsation absorbing function. So, Increase the thickness of the lower case Increased strength for arranging the injection valve socket and mounting bracket It is possible to The thickness of the upper case is designed to provide sufficient pulsation absorption. Nissu Furthermore, because both longitudinal ends of the fuel passage formed between the upper and lower cases are closed with plug members, corners that result in thin walls are not formed at both longitudinal ends of the upper case, stress concentration does not occur at both longitudinal ends of the upper case, and the thickness of the upper case can be made thin enough to provide sufficient pulsation absorption. This makes it possible to increase both the strength of the portion where the injection valve socket and mounting bracket are disposed and the pulsation absorption function that absorbs fuel pulsations.

[0009] In this type of fuel delivery pipe, if both longitudinal ends of a straight pipe material having a fuel passage formed therein are blocked with plug members, gaps are less likely to occur between both ends of the straight pipe material and the plug members. In contrast, in a configuration in which an upper case having an upper wall portion extending longitudinally from one side to the other and a pair of side wall portions extending downward from both widthwise ends of the upper wall portion and having an open longitudinal end and bottom side is fitted inside a lower case having a pair of side wall portions extending upward from both widthwise ends of a bottom wall portion extending from one side to the other in the longitudinal direction, and having an open longitudinal end and top side, and in which plug members are provided in openings formed at both longitudinal ends of the upper and lower cases, a fuel passage is formed between the upper and lower cases.However, in this configuration, unevenness occurs on the inner and outer sides of the fuel passage formed between the upper and lower cases at the ends of the overlapping portions of the upper and lower cases due to the thickness of each case, and even if the openings formed at the longitudinal ends of the upper and lower cases are blocked from the inner or outer sides with plug members, it is difficult for the plug members to liquid-tightly seal around the unevenness caused by the thickness of each case.

[0010] In response to this 、 At both longitudinal ends of the upper case, protrusions are formed that cause the lower ends of the side walls to protrude up to the bottom wall of the lower case, and at both longitudinal ends of the lower case, curved crushed portions are formed at the corners between the bottom wall and the side wall, and inner plug members are fitted as plug members for openings formed on the inner peripheral surfaces of both longitudinal ends of the upper and lower cases to close the openings formed at both longitudinal ends of the upper and lower cases. At both longitudinal ends of the upper and lower cases, protruding portions of the side walls of the upper case protrude to the bottom wall of the lower case, and at both longitudinal ends of the lower case, crushed portions are formed where the curved surfaces are crushed at the corners between the bottom wall and the side wall, so that at both longitudinal ends of the upper and lower cases, the tips of the protruding portions of the upper case abut against the bottom wall at the corners due to the crushed portions of the lower case without gaps. As a result, the inner surfaces of the openings formed at both longitudinal ends of the upper and lower cases are free of irregularities in the circumferential direction of the upper and lower cases caused by the plate thickness of the upper case, so that inner plug members can be fitted into the openings formed at both longitudinal ends of the upper and lower cases without gaps, and the openings formed at both longitudinal ends of the upper and lower cases are liquid-tightly sealed by the inner plug members.

[0011] In order to solve the above-mentioned problems, another embodiment of the present invention provides an upper case having an upper wall portion extending from one side to the other in the longitudinal direction and a pair of side wall portions extending downward from both widthwise ends of the upper wall portion, so that both longitudinal ends and the bottom side are open; and a bottom wall portion having a pair of side wall portions extending upward from both widthwise ends of a bottom wall portion that closes the lower opening of the upper case, so that both longitudinal ends and the top side are open. ,sideThe fuel injection valve is provided with a lower case covering the underside of the upper case so that a fuel passage through which fuel passes is formed between the upper case and the lower case by fitting the outer peripheral surface of the lower part of the side wall of the upper case to the inner peripheral surface of the wall; plug members provided in openings formed at both longitudinal ends of the upper and lower cases to close both longitudinal ends of the fuel passage formed between the upper and lower cases; a plurality of injection valve sockets provided in the lower case and having injection valve insertion holes to which fuel injection valves are liquid-tightly connected and which communicate with the fuel passage; and a mounting bracket provided in the lower case for mounting to the engine, the thickness of the lower case being made thicker to increase the strength for arranging the injection valve sockets and the mounting bracket, and the thickness of the upper case being made thinner to have a pulsation absorbing function. The fuel delivery pipe is characterized in that protrusions are formed at both longitudinal ends of the upper case, causing the lower ends of the side walls to protrude downward more than other parts, and narrow portions are formed at at least both longitudinal ends of the lower parts of the side walls of the lower case, which are recessed inward to have the same width as the upper case, thereby narrowing the width of the lower case, and notches are formed at both longitudinal ends of the side walls of the lower case, at least in the portion that extends outward beyond the narrow portions, to cut out the protrusions and connect them without any steps to the narrow portions, and an outer plug member is fitted as a plug member to the outer peripheral surface of the protrusions of the openings formed at both longitudinal ends of the upper and lower cases, including the portions that are continuous with the narrow portions, thereby closing the openings formed at both longitudinal ends of the upper and lower cases.

[0012] In the fuel delivery pipe configured as described above, the upper case is formed separately from the lower case in which the injection valve socket and mounting bracket are provided. The lower case is thickened to increase the strength required to accommodate the injection valve socket and mounting bracket, while the upper case is thinned to provide pulsation absorption. Therefore, the thickened lower case can increase the strength required to accommodate the injection valve socket and mounting bracket, while the upper case can be made thick enough to provide sufficient pulsation absorption. Furthermore, since both longitudinal ends of the fuel passage formed between the upper and lower cases are closed with plug members, no thin-walled corners are formed at both longitudinal ends of the upper case, preventing stress concentration at both longitudinal ends of the upper case. This allows the upper case to be thinned to provide sufficient pulsation absorption. This increases both the strength of the portion in which the injection valve socket and mounting bracket are located and the pulsation absorption function for absorbing fuel pulsations.

[0013] In this type of fuel delivery pipe, if both longitudinal ends of a straight pipe material having a fuel passage formed therein are blocked with plug members, gaps are less likely to occur between both ends of the straight pipe material and the plug members. In contrast, in a configuration in which an upper case having an upper wall portion extending longitudinally from one side to the other and a pair of side wall portions extending downward from both widthwise ends of the upper wall portion and having an open longitudinal end and bottom side is fitted inside a lower case having a pair of side wall portions extending upward from both widthwise ends of a bottom wall portion extending from one side to the other in the longitudinal direction, and having an open longitudinal end and top side, and in which plug members are provided in openings formed at both longitudinal ends of the upper and lower cases, a fuel passage is formed between the upper and lower cases.However, in this configuration, unevenness occurs on the inner and outer sides of the fuel passage formed between the upper and lower cases at the ends of the overlapping portions of the upper and lower cases due to the thickness of each case, and even if the openings formed at the longitudinal ends of the upper and lower cases are blocked from the inner or outer sides with plug members, it is difficult for the plug members to liquid-tightly seal around the unevenness caused by the thickness of each case. In contrast, protrusions are formed at both longitudinal ends of the upper case, causing the lower ends of the side walls to protrude downward more than the other portions, and narrow portions are formed at at least both longitudinal ends of the lower parts of the side walls of the lower case, which are recessed inward to have the same width as the upper case, thereby narrowing the width of the lower case, and notches are formed at both longitudinal ends of the side walls of the lower case, at least in the portion that extends outward from the narrow portions, to seamlessly connect the protrusions to the narrow portions, and outer plug members are fitted as plug members onto the outer peripheral surfaces of the protrusions of the openings formed at both longitudinal ends of the upper and lower cases, including the portions that are continuous with the narrow portions, to close the openings formed at both longitudinal ends of the upper and lower cases. At both longitudinal ends of the upper and lower cases, the protrusions of the side walls of the upper case are seamlessly connected to the narrow portions by the notches in the side walls of the lower case. As a result, the outer surfaces of the openings formed at both longitudinal ends of the upper and lower cases are free of unevenness caused by the thickness of the lower case in the circumferential direction of the upper and lower cases, and the outer plug members can be fitted tightly to the outer surfaces of the openings formed at both longitudinal ends of the upper and lower cases, so that the openings formed at both longitudinal ends of the upper and lower cases are liquid-tightly sealed by the outer plug members. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a front view of a first embodiment of a fuel delivery pipe according to the present invention. FIG. [Figure 2] FIG. 2 is a plan view of FIG. [Figure 3] FIG. 2 is a longitudinal cross-sectional view taken along the longitudinal direction of FIG. [Figure 4] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Figure 5] FIG. 2 is a cross-sectional view taken along line BB in FIG. [Figure 6] 4 is a longitudinal cross-sectional view of a fuel delivery pipe according to a modification of the first embodiment, taken along the longitudinal direction corresponding to FIG. 3. FIG. [Figure 7] FIG. 4 is a front view of a second embodiment of a fuel delivery pipe according to the present invention. [Figure 8] FIG. 8 is a plan view of FIG. [Figure 9] FIG. 8 is a longitudinal cross-sectional view taken along the longitudinal direction of FIG. 7. [Figure 10] FIG. 8 is a cross-sectional view taken along line CC in FIG. [Figure 11] FIG. 8 is a cross-sectional view taken along line DD in FIG. 7. [Figure 12] 10 is a longitudinal cross-sectional view of a fuel delivery pipe according to a modification of the second embodiment, taken along the longitudinal direction corresponding to FIG. 9. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the fuel delivery pipe according to the present invention will be described with reference to the accompanying drawings. (First embodiment) The fuel delivery pipe 10 of the first embodiment is used in an in-line three-cylinder engine, and as shown in Figures 1 to 3, comprises an upper case 20 having an upper wall portion 21 extending from one side to the other in the longitudinal direction and a pair of side wall portions 22 extending downward from both widthwise ends of the upper wall portion 21, and having both longitudinal ends and a bottom side open; a lower case 30 having at least a bottom wall portion 31 closing the opening on the bottom side of the upper case 20 and covering the bottom side of the upper case 20 so that a fuel passage 40 through which fuel passes is formed between the upper case 20; and inner plug members 41, 42 as plug members provided in openings 20a formed at both longitudinal ends of the upper and lower cases 20, 30 and closing both longitudinal ends of the fuel passage 40 formed between the upper and lower cases 20, 30.

[0016] As shown in FIGS. 1 to 4, the upper case 20 has an upper wall 21 extending longitudinally from one end to the other and a pair of side walls 22 extending downward from both widthwise ends of the upper wall 21. The upper case 20 is formed by pressing a 0.8 mm thick sheet metal member into a groove shape with an open bottom and then cutting it to an appropriate length, resulting in a U-shaped groove shape with both longitudinal ends and the bottom open. The upper case 20 is made of a sheet metal member that is thinner than the lower case 30, and the upper wall 21 and both side walls 22 have a pulsation absorbing function that absorbs fuel pulsations. As shown in FIGS. 3 and 5, protrusions 22a are formed at both longitudinal ends of the side walls 22 of the upper case 20, with the lower ends protruding downward. The protrusions 22a protrude to the bottom wall 31 of the corners 33 of the lower case 30. In Figure 3, only the protrusion 22a at the end on the left side of the side wall portion 22 of the upper case 20 in the longitudinal direction is shown enlarged, but a protrusion 22a is also formed at the end on the right side of the side wall portion 22 in the longitudinal direction.

[0017] 3 to 5, the lower case 30 has a bottom wall 31 that closes the opening at the bottom of the upper case 20 and covers the bottom of the upper case 20 so as to form a fuel passage 40 through which fuel passes between the lower case 30 and the upper case 20. In this embodiment, the lower case 30 has the bottom wall 31 extending longitudinally from one end to the other and a pair of side wall portions 32 extending upward from both ends in the width direction of the bottom wall 31, forming a U-shaped groove that is open at both ends in the longitudinal direction and at the top. The lower case 30 is made by pressing a 1.0 mm thick sheet metal member, which is thicker than the upper case 20 to increase strength, into a shallow U-shaped groove shape and then cutting it to an appropriate length.

[0018] 3 and 4, three mounting holes 31a consisting of through holes for mounting injection valve sockets 43 are formed in the bottom wall 31 of the lower case 30, and an injection valve socket 43 is fixed to the underside of the bottom wall 31 at the position of each mounting hole 31a. An injection valve insertion hole 43a through which a fuel injection valve (not shown) is inserted is formed in the injection valve socket 43, and the injection valve insertion hole 43a is connected to the fuel passage 40 via the mounting hole 31a. As shown in FIGS. 1 to 3, two mounting brackets 44 for mounting to the engine are fixed to the underside of the bottom wall 31 of the lower case 30, and the left mounting bracket 44 is disposed between the left and central injection valve sockets 43, and the right mounting bracket 44 is disposed between the central and right injection valve sockets 43.

[0019] 1, 4, and 5, the side wall portions 32 of the lower case 30 extend vertically upward from both widthwise ends of the bottom wall portion 31 (a direction perpendicular to the longitudinal direction and horizontally), and an outer edge portion 32a extending outward is formed along the longitudinal direction at the upper end of the side wall portion 32. The outer edge portion 32a extending outward at the upper end of the side wall portion 32 makes it easier to place brazing material when fastening the upper and lower cases 20, 30 by brazing. As shown in FIG. 4, a bent portion 33a is formed at the corner 33 between the bottom wall portion 31 and the side wall portion 32 of the lower case 30 to form a curved surface, and in this embodiment, the outer bend radius of the bent portion 33a is 2 mm (the inner bend radius is 1 mm).

[0020] As shown in Figures 4 and 5, the bent portions are crushed at both longitudinal ends of the corners 33 of the lower case 30 to form crushed portions 33b. In this embodiment, the crushed portions 33b are crushed so that the outer bend radius is 1.2 mm (the inner bend radius is 0.2 mm). Figures 4 and 5 show the crushed portions 33b at the left end of the side wall 33 in Figure 3, but the right end of the side wall in Figure 3 also has a crushed portion 33b, similar to Figures 4 and 5. Since the bent portions are crushed at both longitudinal ends of the corners 33 between the bottom wall 31 and side wall 32 of the lower case 30, the protrusions 22a formed at both longitudinal ends of the upper case 20 abut against the bottom wall 31 of the corners 33 of the lower case 30 without any gaps. In this way, irregularities resulting from the thickness of the upper case 20 are not formed on the inner peripheral surfaces of the openings 20a formed at both longitudinal ends of the upper and lower cases 20, 30. It is preferable to cut off the outer corners of the tip of the protruding portion 22a of the upper case 20 so that it does not come into contact with the slight curved surface remaining in the crushed portion 33b.

[0021] 1 to 3, inner plug members 41, 42 are provided as plug members in the openings 20a formed at both longitudinal ends of the upper and lower cases 20, 30, and the inner plug members 41, 42 have the same generally rectangular block shape as the openings 20a of the upper and lower cases 20, 30, with the longitudinal direction of the upper and lower cases 20, 30 as their thickness direction. Approximately half of the inner plug members 41, 42 in the thickness direction are fitted into the openings 20a formed at each longitudinal end of the upper and lower cases 20, 30, and close both longitudinal sides of the fuel passage 40 formed between the upper and lower cases 20, 30.

[0022] As described above, the protruding portions 22a of the side wall portions 22 of the upper case 20 abut the bottom wall portion 31 without any gaps at the positions where the crushed portions 33b of the corner portions 33 of the lower case 30 are formed, so that the inner surfaces of the openings 20a formed at both longitudinal ends of the upper and lower cases 20, 30 are free of irregularities caused by the thickness of the upper case 20. Since the inner plug members 41, 42 are fitted into the openings 20a at both longitudinal ends of the upper and lower cases 20, 30 where no irregularities caused by the thickness of the upper case 20 are formed, gaps are unlikely to form between the openings 20a formed at both longitudinal ends of the upper and lower cases 20, 30 and the inner plug members 41, 42, and the openings 20a at both longitudinal ends of the upper and lower cases 20, 30 are liquid-tightly sealed by the inner plug members 41, 42. Also, as shown in FIG. 3, in this embodiment, a joint pipe member 45 is inserted through the inner plug member 41 located on the right side, and a fuel supply pipe (not shown) through which fuel is supplied from a fuel pump is connected to the joint pipe member 45, and fuel is supplied from the fuel pump (not shown) to the fuel passage 40 formed between the upper and lower cases 20, 30.

[0023] When manufacturing this fuel delivery pipe 10, the three injection valve sockets 43 and two mounting brackets 44 are temporarily fixed by welding or the like to the underside of the lower case 30, the upper case 20 is fitted inside this lower case 30, and the inner plug members 41, 42 are fitted into the openings 20a at both longitudinal ends of the upper and lower cases 20, 30 and temporarily fixed by welding or the like. The injection valve sockets 43, mounting brackets 44, and upper case 20 are brazed to the lower case 30, and the inner plug members 41, 42 are fixed liquid-tightly by brazing to the openings 20a formed at both longitudinal ends of the upper and lower cases 20, 30, and after fixing, surface treatment such as plating is performed as necessary.

[0024] The fuel delivery pipe 10 configured as described above comprises an upper case 20 having an upper wall portion 21 extending longitudinally from one side to the other and a pair of side wall portions 22 extending downward from both widthwise ends of the upper wall portion 21, with both longitudinal ends and the lower side being open; a lower case 30 having at least a bottom wall portion 31 closing the lower opening of the upper case 20 and covering the lower side of the upper case 20 so as to form a fuel passage 40 through which fuel passes between the upper case 20 and the lower case; The fuel injection valve socket 43 is provided in the lower case 30 and has an injection valve insertion hole 43a to which the fuel injection valve is liquid-tightly connected and which communicates with the fuel passage; and a mounting bracket 44 is provided in the lower case 30 and used for mounting to the engine.

[0025] In this fuel delivery pipe 10, the upper case 20 is configured separately from the lower case 30, in which the injection valve socket 43 and the mounting bracket 44 are provided. Therefore, even if the thickness of the lower case 30 is increased to increase the strength for arranging the injection valve socket 43 and the mounting bracket 44, the thickness of the upper case 20 can be made thin enough to provide sufficient pulsation absorption. Furthermore, because the openings 20a formed at both longitudinal ends of the fuel passage 40 formed between the upper and lower cases 20, 30 are closed by inner plug members (plug members) 41, 42, no corners that would otherwise be thin are formed at both longitudinal ends of the upper case 20. This prevents stress concentration at both longitudinal ends of the upper case 20, allowing the thickness of the upper case 20 to be made thin enough to provide sufficient pulsation absorption. As a result, this fuel delivery pipe 10 can increase both the strength of the portion where the injection valve socket 43 and the mounting bracket 44 are disposed and the pulsation absorption function that absorbs fuel pulsations.

[0026] The fuel delivery pipe 10 is configured such that an upper case 20 having an upper wall portion 21 extending longitudinally from one side to the other and a pair of side wall portions 22 extending downward from both widthwise ends of the upper wall portion 21, and having both longitudinal ends and a bottom side open, is fitted inside the lower case 30, which has a pair of side wall portions 32 extending upward from both widthwise ends of the bottom wall portion 31 extending longitudinally from one side to the other, and is open at both longitudinal ends and the top side, and inner plug members (plug members) 41, 42 are provided in openings 20a formed at both longitudinal ends of the upper and lower cases 20, 30, thereby forming a fuel passage 40 between the upper and lower cases 20, 30. On the inner periphery of the upper and lower cases 20, 30, unevenness occurs at the ends of the overlapping portions of the side wall portions 22, 32 of the upper and lower cases 20, 30 due to the thickness of the upper case 20, and even if inner plug members (plug members) 41, 42 are fitted into the inner periphery of the opening 20a formed at both longitudinal ends of the upper and lower cases 20, 30 to close it, it is difficult for the inner plug members (plug members) 41, 42 to liquid-tightly seal around the unevenness caused by the thickness of the upper case 20 inside the opening 20a.

[0027] For this reason, this fuel delivery pipe 10 has protrusions 22a formed at both longitudinal ends of the upper case 20, which cause the lower ends of the side wall portions 22 to protrude up to the bottom wall portion 31 of the lower case 30, and curved crushed portions 33b formed at the corners 33 between the bottom wall portion 31 and the side wall portion 32 at both longitudinal ends of the lower case 30, and inner plug members 41, 42 are fitted as plug members onto the inner surfaces of the openings 20a formed at both longitudinal ends of the upper and lower cases 20, 30, so that the openings 20a formed at both longitudinal ends of the upper and lower cases 20, 30 are closed by the inner plug members 41, 42.

[0028] At both longitudinal ends of the upper and lower cases 20, 30, the tips of the protrusions 22a of the side wall 22 of the upper case 20 abut against the bottom wall 31 of the corner 33 of the lower case 30 without any gaps due to the crushed portions 33b of the corners 33. As a result, irregularities resulting from the plate thickness of the upper case 20 are not formed on the inner circumferential surfaces of the openings 20a formed at both longitudinal ends of the upper and lower cases 20, 30 in the circumferential direction of the upper and lower cases 20, 30. The inner plug members 41, 42 can be fitted into the openings 20a formed at both longitudinal ends of the upper and lower cases 20, 30 without any gaps, and the openings 20a formed at both longitudinal ends of the upper and lower cases 20, 30 are liquid-tightly sealed by the brazed inner plug members 41, 42.

[0029] In the fuel delivery pipe 10 of this embodiment, the injection valve socket 43 is fixed separately to the underside of the bottom wall of the lower case 30, but this is not limited to this, and in a modified example shown in Fig. 6, the bottom wall of the lower case 30 may be recessed inward so that the injection valve socket 43 is provided integrally with the bottom wall of the lower case 30. Furthermore, it is sufficient for the lower case 30 to have at least the bottom wall portion 31, and the side wall portion 32 may be eliminated by extending the side wall portion 22 of the upper case 20 to the bottom wall portion 31, or the side wall portion 32 may extend downward.

[0030] (Second embodiment) In the fuel delivery pipe 10 of the first embodiment, inner plug members 41, 42 are fitted inside openings 20a formed at both longitudinal ends of the upper and lower cases 20, 30, so that the openings 20a formed at both longitudinal ends of the upper and lower cases 20, 30 are liquid-tightly closed by the inner plug members 41, 42, whereas in the fuel delivery pipe 10A of the second embodiment, outer plug members 41A, 42A are fitted outside openings 20a formed at both longitudinal ends of the upper and lower cases 20, 30, so that the openings 20a at both longitudinal ends of the upper and lower cases 20, 30 are liquid-tightly closed by the outer plug members 41A, 42A. The following describes the fuel delivery pipe 10A of the second embodiment, focusing on the differences from the fuel delivery pipe 10 of the first embodiment.

[0031] The fuel delivery pipe 10A of the second embodiment comprises an upper case 20 having an upper wall portion 21 extending longitudinally from one side to the other and a pair of side wall portions 22 extending downward from both widthwise ends of the upper wall portion 21, with both longitudinal ends and the bottom side being open; a lower case 30 having at least a bottom wall portion 31 closing the opening on the bottom side of the upper case 20 and covering the bottom side of the upper case 20 so that a fuel passage 40 through which fuel passes is formed between the upper case 20; and outer plug members 41A, 42A as plug members provided in openings 20a formed at both longitudinal ends of the upper and lower cases 20, 30 and closing both longitudinal ends of the fuel passage 40 formed between the upper and lower cases 20, 30.

[0032] As shown in FIGS. 7 to 10 , the upper case 20 has an upper wall 21 extending longitudinally from one end to the other and a pair of side walls 22 extending downward from both widthwise ends of the upper wall 21. The upper case 20 is formed by pressing a 0.8 mm thick sheet metal member into a groove shape with an open bottom and then cutting it to an appropriate length, resulting in a U-shaped groove shape with both longitudinal ends and the bottom open. The upper case 20 is made of a sheet metal member that is thinner than the lower case 30, and the upper wall 21 and both side walls 22 have a pulsation absorbing function that absorbs fuel pulsations. As shown in FIGS. 9 to 11 , the side walls 22 of the upper case 20 have protruding portions 22a at their lower ends that protrude downward, and the protruding portions 22a protrude to the position of narrow portions 32b of side walls 32 of the lower case 30, which will be described later. By making the protrusion 22a continuous with the narrow width portions 32b at both longitudinal ends of the side wall portion 32 of the lower case 30, the outer peripheral surfaces of the side wall portion 22 of the upper case 20 and the outer peripheral surfaces of the side wall portion 32 of the lower case 30 are continuous without unevenness due to the plate thickness of each case. Note that while Fig. 9 shows an enlarged view of only the protrusion 22a at the end on the left side in the longitudinal direction of the side wall portion 22 of the upper case 20, a similar protrusion 22a is also formed at the end on the right side in the longitudinal direction of the side wall portion 22.

[0033] As shown in FIGS. 9 to 11 , the lower case 30 has a bottom wall 31 that closes the lower opening of the upper case 20 and covers the lower side of the upper case 20 so as to form a fuel passage 40 through which fuel passes between the lower case 30 and the upper case 20. In this embodiment, the lower case 30 has the bottom wall 31 extending longitudinally from one end to the other and a pair of side wall portions 32 extending upward from both widthwise ends of the bottom wall 31, forming a U-shaped groove that is open at both longitudinal ends and at the top. The lower case 30 is made by pressing a 1.0 mm thick sheet metal member, which is thicker than the upper case 20 to increase strength, into a shallow U-shaped groove shape and then cutting it to an appropriate length. The bottom wall 31 of the lower case 30 has three mounting holes 31a formed as through-holes for mounting injection valve sockets 43, and the injection valve sockets 43 are fixed to the underside of the bottom wall 31 at the positions of the mounting holes 31a. Two mounting brackets 44 for mounting to an engine are fixed to the lower surface of the bottom wall portion 31 of the lower case 30.

[0034] 10 and 11 , an outer edge portion 32a that extends outward is formed along the longitudinal direction at the upper end of the side wall portion 32 of the lower case 30, and a narrow portion 32b that is recessed inward and narrows the width of the lower case 30 so that the width is the same as that of the upper case 20 is formed along the longitudinal direction at the lower part of the side wall portion 32 of the lower case 30. The width of the lower case 30 at the position where the narrow portion 32b is formed (the length between the side wall portions 32 on both sides at the position where the narrow portion 32b is formed) is the same as the width of the upper case 20 (the length between the side wall portions 22 on both sides), and the width of the lower case 30 at a position above the narrow portion 32b (the length between the side wall portions 32 on both sides above the position where the narrow portion 32b is formed) is greater than the width of the upper case 20 (the length between the side wall portions 22 on both sides). The outer peripheral surface of the lower part of the side wall 22 of the upper case 20 can be fitted into the inner peripheral surface above the narrow portion 32b of the side wall 32 of the lower case 30. In this embodiment, the narrow portion 32b is formed along the longitudinal direction of the side wall 32, but this is not limited thereto, and it is sufficient that the narrow portion 32b is formed only at least at both longitudinal ends of the lower case 30.

[0035] 9 and 11, cutouts 32c are formed at both longitudinal ends of the lower case 30, including the portion that extends outward beyond the narrow portion 32b, to seamlessly connect the protruding portion 22a of the upper case 20 to the narrow portion 32b. At both longitudinal ends of the upper and lower cases 20, 30, cutouts 32c allow the lower end of the protruding portion 22a of the side wall 22 of the upper case 20 to seamlessly connect with the narrow portion 32b of the lower case 30, and the outer peripheral surfaces of the side wall 22 of the upper case 20 and the side wall 22 of the lower case 30 are continuous without any unevenness due to the thickness of the upper case 20. 9 and 10 show a protrusion 22a at the left end of the side wall portion 22 in FIG. 9 and a notch 32c at the left end of the side wall portion 33, but the protrusion 22a and the notch 32c are also formed at the right end of the side wall portions 22, 32 in FIG. 9, similar to FIGS. 9 and 10.

[0036] 7 to 9, outer plug members 41A, 42A are provided as plug members in the openings 20a at both longitudinal ends of the upper and lower cases 20, 30, and the outer plug members 41A, 42A are shallow, bottomed, cylindrical members whose axis is the longitudinal direction of the upper and lower cases 20, 30. The outer plug members 41A, 42A are fitted onto the outer peripheral surfaces of the respective longitudinal ends of the upper and lower cases 20, 30, and close both longitudinal ends of the fuel passage 40 formed between the upper and lower cases 20, 30. As described above, at both longitudinal ends of the upper and lower cases 20, 30, the protruding portion 22a of the side wall portion 22 of the upper case 20 is connected without any steps to the narrow portion 32b of the side wall portion 32 of the lower case 30 by the cutout portion 32c, and the outer surfaces of the openings 20a formed at both longitudinal ends of the upper and lower cases 20, 30 are free of irregularities resulting from the thickness of the lower case 30. Since the outer plug members 41A, 42A are fitted onto the outer peripheral surfaces of the openings 20a at both longitudinal ends of the upper and lower cases 20, 30, where irregularities due to the plate thickness of the lower case 30 are not formed, gaps are unlikely to form between the outer peripheral surfaces of the openings 20a at both longitudinal ends of the upper and lower cases 20, 30 and the outer plug members 41A, 42A, and the openings 20a formed at both longitudinal ends of the upper and lower cases 20, 30 are liquid-tightly sealed by the brazed outer plug members 41A, 42A. Also, in this embodiment, a joint pipe member 45 is inserted through the outer plug member 41A located on the right side, and a fuel supply pipe (not shown) to which fuel is supplied from a fuel pump is connected to the joint pipe member 45, and fuel is supplied from the fuel pump to the fuel passage 40 formed between the upper and lower cases 20, 30.

[0037] The fuel delivery pipe 10A configured as described above comprises an upper case 20 having an upper wall portion 21 extending longitudinally from one side to the other and a pair of side wall portions 22 extending downward from both widthwise ends of the upper wall portion 21, with both longitudinal ends and the bottom side being open; a lower case 30 having at least a bottom wall portion 31 closing the opening on the bottom side of the upper case 20 and covering the bottom side of the upper case 20 so as to form a fuel passage 40 through which fuel passes between the upper case 20 and the lower case 30; and a fuel delivery pipe 10A formed by the upper and lower cases 20, 30. The fuel passage 40 is formed between the upper and lower cases 20, 30. The fuel passage 40 is provided at both longitudinal ends of the fuel passage 40 by inserting outer plug members 41A, 42A into openings 20a formed in the upper and lower cases 20, 30, and closing both longitudinal ends of the fuel passage 40. The fuel passage 40 is provided with three (plural) injection valve sockets 43 which are integrally formed with the lower case 30 and have injection valve insertion holes 43a through which fuel injection valves are fluid-tightly connected and which communicate with the fuel passage 40. The fuel passage 40 is also provided with a mounting bracket 44 which is integrally formed with the lower case 30 and which is used for mounting the fuel passage 40 to the engine.

[0038] In this fuel delivery pipe 10A, similar to the fuel delivery pipe 10 of the first embodiment, the upper case 20 is configured separately from the lower case 30 in which the injection valve socket 43 and the mounting bracket 44 are provided, so that even if the thickness of the lower case 30 is increased to increase the strength for arranging the injection valve socket 43 and the mounting bracket 44, the thickness of the upper case 20 can be made thin enough to provide sufficient pulsation absorption. Furthermore, since the openings 20a formed at both longitudinal ends of the fuel passage formed between the upper and lower cases 20, 30 are closed by outer plug members (plug members) 41A, 42A, no corners that would result in thin walls are formed at both longitudinal ends of the upper case 20, and stress concentration is prevented at both longitudinal ends of the upper case 20, so that the thickness of the upper case 20 can be made thin enough to provide sufficient pulsation absorption. This makes it possible for the fuel delivery pipe 10 to increase both the strength of the portion where the injection valve socket 43 and the mounting bracket 44 are disposed and the pulsation absorbing function for absorbing fuel pulsations.

[0039] In addition, the fuel delivery pipe 10A has a pair of side wall portions 32 extending upward from both widthwise ends of a bottom wall portion 31 extending from one side to the other in the longitudinal direction, and is open at both longitudinal ends and the top. An upper case 20 has an upper wall portion 21 extending from one side to the other in the longitudinal direction and a pair of side wall portions 22 extending downward from both widthwise ends of the upper wall portion 21, and is open at both longitudinal ends and the bottom, and is fitted inside the lower case 30. Outer plug members (plug members) 41A, 42A are provided in openings 20a formed at both longitudinal ends of the upper and lower cases 20, 30, so that a fuel passage 40 is formed between the upper and lower cases 20, 30. On the outer periphery of the upper and lower cases 20, 30, unevenness occurs at the ends of the overlapping portions of the side wall portions 22, 32 of the upper and lower cases 20, 30 due to the thickness of the lower case 30, and even if outer plug members (plug members) 41A, 42A are fitted into the outer periphery of the opening 20a formed at both longitudinal ends of the upper and lower cases 20, 30 to close it, it is difficult for the outer plug members (plug members) 41A, 42A to liquid-tightly seal around the unevenness caused by the thickness of the lower case 30 on the outer periphery of the opening 20a.

[0040] For this reason, in this fuel delivery pipe 10A, protrusions 22a are formed at both longitudinal ends of the upper case 20, causing the lower ends of the side wall portions 22 to protrude downward more than other portions, and narrow portions 32b are formed at the lower parts of the side wall portions 32 of the lower case 30, which are recessed inward to narrow the width of the lower case so that the width is the same as the width of the upper case 20 (the length between the side wall portions 22 on both sides), and notches 32c are formed at both longitudinal ends of the side wall portions 32 of the lower case 30, where at least the portion extending outward beyond the narrow portions 32b is cut out to seamlessly connect the protrusions 22a to the narrow portions 32b.

[0041] The outer peripheral surfaces of both longitudinal ends of the upper and lower cases 20, 30 are continuous without any steps with the narrow portions 32b of the protruding portions 22a of the side wall portions 22 of the upper case 20 due to the cutout portions 32c of the side wall portions 32 of the lower case 30. As a result, the outer peripheral surfaces of the openings 20a formed at both longitudinal ends of the upper and lower cases 20, 30 are free of irregularities in the circumferential direction of the upper and lower cases 20, 30 that arise from the plate thickness of the lower case 30. This allows the outer plug members 41A, 42A to fit snugly around the outer peripheral surfaces of the openings 20a formed at both longitudinal ends of the upper and lower cases 20, 30, and the openings 20a formed at both longitudinal ends of the upper and lower cases 20, 30 are liquid-tightly sealed by the brazed outer plug members 41A, 42A.

[0042] In the fuel delivery pipe 10A of this embodiment, the injection valve socket 43 is fixed separately to the underside of the bottom wall of the lower case 30, but this is not limited to this. In a modified example shown in Figure 12, the bottom wall of the lower case 30 may be recessed inward, so that the injection valve socket 43 is integrally formed on the bottom wall of the lower case 30.

[0043] The fuel delivery pipe 10 of the first and second embodiments is provided with three injection valve sockets 43 to accommodate an in-line three-cylinder engine, but is not limited to this and may be used in a V-type six-cylinder engine by using two of the fuel delivery pipes 10 of each embodiment. The fuel delivery pipe 10 of the first and second embodiments may be provided with two or more injection valve sockets and used in an in-line or V-type engine with two or more cylinders. [Explanation of symbols]

[0044] 10, 10A...fuel delivery pipe, 20...upper case, 20a...opening, 21...upper wall portion, 22...side wall portion, 22a...protruding portion, 30...lower case, 31...bottom wall portion, 32...side wall portion, 32b...narrow width portion, 32c...cutout portion, 33...corner portion, 33b...crushed portion, 40...fuel passage, 41, 42...plug member, inner plug member, 41A, 42A...plug member, outer plug member, 43...injection valve socket, 44...mounting bracket.

Claims

1. an upper case having an upper wall portion extending longitudinally from one end to the other and a pair of side walls extending downward from both widthwise ends of the upper wall portion, the upper case being open at both longitudinal ends and at the bottom; a lower case that covers the lower side of the upper case and has a pair of side wall portions extending upward from both widthwise ends of a bottom wall portion that closes an opening on the lower side of the upper case, and is open at both longitudinal ends and at an upper side, and that covers the lower side of the upper case so that a fuel passage through which fuel passes is formed between the upper case and the lower case by fitting the outer peripheral surfaces of the lower parts of the side wall portions of the upper case into the inner peripheral surfaces of the side wall portions; plug members provided in openings formed at both longitudinal end portions of the upper and lower cases to close both longitudinal end portions of a fuel passage formed between the upper and lower cases; a plurality of injection valve sockets provided in the lower case, each having an injection valve insertion hole to which a fuel injection valve is fluid-tightly connected and which communicates with the fuel passage; a mounting bracket provided on the lower case for mounting the lower case to an engine, The thickness of the lower case is increased to increase the strength for arranging the injection valve socket and the mounting bracket, and the thickness of the upper case is formed thin so as to have a pulsation absorbing function, The upper case has protrusions at both longitudinal ends thereof that cause the lower ends of the side walls to protrude up to the bottom wall of the lower case, and the lower case has curved crushed portions at the corners between the bottom wall and the side wall at both longitudinal ends thereof, A fuel delivery pipe characterized in that an inner plug member is fitted as the plug member onto the inner surface of an opening formed at both longitudinal ends of the upper and lower cases, thereby closing the openings formed at both longitudinal ends of the upper and lower cases.

2. an upper case having an upper wall portion extending longitudinally from one end to the other and a pair of side walls extending downward from both widthwise ends of the upper wall portion, the upper case being open at both longitudinal ends and at the bottom; a lower case that covers the lower side of the upper case and has a pair of side wall portions extending upward from both widthwise ends of a bottom wall portion that closes an opening on the lower side of the upper case, and is open at both longitudinal ends and at an upper side, and that covers the lower side of the upper case so that a fuel passage through which fuel passes is formed between the upper case and the lower case by fitting the outer peripheral surfaces of the lower parts of the side wall portions of the upper case into the inner peripheral surfaces of the side wall portions; plug members provided in openings formed at both longitudinal end portions of the upper and lower cases to close both longitudinal end portions of a fuel passage formed between the upper and lower cases; a plurality of injection valve sockets provided in the lower case, each having an injection valve insertion hole to which a fuel injection valve is fluid-tightly connected and which communicates with the fuel passage; a mounting bracket provided on the lower case for mounting the lower case to an engine, The thickness of the lower case is increased to increase the strength for arranging the injection valve socket and the mounting bracket, and the thickness of the upper case is formed thin so as to have a pulsation absorbing function, A protruding portion is formed at both longitudinal ends of the upper case, causing the lower end of the side wall portion to protrude downward more than the other portion, and a narrow portion is formed at at least both longitudinal ends of the lower part of the side wall portion of the lower case, which is recessed inward to have the same width as the upper case, thereby narrowing the width of the lower case, and a notch is formed at at least both longitudinal ends of the side wall portion of the lower case, cutting out at least the portion that extends outward from the narrow portion, so that the protruding portion continues to the narrow portion without a step, A fuel delivery pipe characterized in that the openings formed at both longitudinal ends of the upper and lower cases are closed by fitting an outer plug member as the plug member to the outer peripheral surface, including the portion where the protruding portion of the openings formed at both longitudinal ends of the upper and lower cases continues to the narrow portion.

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