JP2014190188A - Fuel pressure pulsation reducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel pressure pulsation reducing device used in a fuel injection system, capable of enhancing pulsation absorbing performance, and capable of preventing clogging of a fuel injection valve caused by sputter generated in welding of a housing.SOLUTION: A fuel pressure pulsation reducing device includes a sealed housing 11 having a fuel chamber 15 formed in an inside thereof, and a fuel pressure pulsation absorbing member D provided in the fuel chamber. The housing 11 having the fuel chamber in the inside thereof is formed by superimposing flange parts 12b and 13b of the outer circumference of first and second members 12 and 13 formed in a cup shape by press working, and radiating laser beams to all over an annular abutting part from a direction orthogonal to the abutting part of both of the members so as to integrally and liquid-tightly weld and couple both of the members.

Description

  The present invention relates to a fuel pressure pulsation reducing device used in a fuel injection system for an internal combustion engine.

  In a fuel injection system for an internal combustion engine, fuel is supplied by supplying fuel from a high-pressure pump to a delivery pipe provided with a plurality of fuel injection valves, and the opening and closing timing of electromagnetic valves provided in each fuel injection valve is controlled by a control device. The fuel from a plunger pump driven by an internal combustion engine is supplied to a delivery pipe provided with a plurality of fuel injection valves, and the plunger pump is controlled by an electromagnetic device controlled by a control device. Controlling the operation of the intake valve, thereby controlling the amount and timing of fuel returned from the plunger pump having a constant discharge amount per stroke to the fuel supply passage side, and controlling the fuel injection amount and injection timing; There is. In any case, a fuel pressure pulsation reducing device is provided in order to reduce the fluctuation of the fuel injection amount caused by the fluctuation of the fuel pressure in the pipe.

  As the fuel pressure pulsation reducing device in the former case, there is a pulsation damper shown in Patent Document 1, which is formed of a thin film of a flexible resin or an oil-resistant rubber (hereinafter simply referred to as a flexible resin) and is made by a spring. It has a pressure chamber formed between a diaphragm urged in the direction and a casing, and is used by being attached to the delivery pipe so that the pressure chamber communicates with the internal space of the delivery pipe.

  As a fuel pressure pulsation reducing device in the latter case, there is a damper device of a plunger type high pressure pump disclosed in Patent Document 2. As shown in FIG. 6, the bottomed cylindrical lid member 2 is covered with an opening of a shallow cylindrical recess 1a provided in a damper housing 1 formed integrally with a pump housing of a high-pressure pump, and welded or the like. A flange 21a formed on each outer periphery of two diaphragm members 21 and 22 formed by forming a fuel chamber 3 that is liquid-tightly closed and communicated with a pressurizing chamber of a high-pressure pump, and a thin metal plate is pressed into a shallow cup shape. For example, three pulsation dampers 20 in which 22a is welded in a liquid-tight manner by seam welding or the like to form a sealed space therein are accommodated in the fuel chamber 3 and the flange portions 21a and 22a are held (in FIG. 6). It is supported by the mounting member 4 (only one is shown).

JP 2003-42338 A JP 2012-184757 A

  In the technique of Patent Document 1, a diaphragm made of a thin film such as a flexible resin has high flexibility, so that a small and lightweight pulsation reducing device with excellent pulsation absorption performance can be obtained. There is a possibility that the diaphragm is deteriorated by the substance, and that the durability of the diaphragm is lowered as the fuel pressure is increased. This problem can be solved to some extent by selecting a flexible resin material, but some fuels are a mixture of gasoline and alcohol or other chemicals. On the other hand, it has been extremely difficult to select a material such as a flexible resin for the diaphragm that does not deteriorate.

  On the other hand, since the pulsation damper described in Patent Document 2 uses a thin metal plate, it is difficult to deteriorate against any fuel, and thus high durability is obtained. However, since a thin metal plate is less flexible than a flexible resin or the like, there is a problem that it is difficult to reduce the size and weight when high pulsation absorption performance is required.

  Further, in Patent Document 2, as shown in FIG. 6, between a damper housing 1 formed integrally with a pump housing of a high-pressure pump and a bottomed cylindrical lid member 2 covered with an opening of a recess 1a provided thereon. Welding is performed by irradiating a laser beam inward from the outside in the radial direction as shown by an arrow B over the entire circumference of the outer peripheral surface of the lid member 2 slightly apart from the front end surface 2a. The fuel chamber 3 formed between the members 1 and 2 is sealed by liquid-tight welding. For this welding connection, it is necessary to locally melt both the members 1 and 2 to a depth exceeding the contact surface between them with a laser beam, but it is not always easy to control the depth of the melted portion. However, sometimes the tip of the melted part may reach close to the inner surface of the fuel chamber 3. Since a force for scattering in the irradiation direction of the laser beam is applied to the tip of the melted portion, when the tip of the melted portion reaches the inner surface of the fuel chamber 3, a part of the melted damper housing 1 is finely sputtered. As a result, there is a risk of scattering from the inner surface of the fuel chamber 3 in the laser beam irradiation direction and entering the fuel chamber 3 in which the pulsation damper 20 is accommodated. Even if the spatter penetrates into the fuel chamber, there is a possibility that the fuel injection valve provided in the delivery pipe may be clogged.

  Furthermore, in the high-pressure pump integrated with the damper device as in Patent Document 2, the characteristics of both the pump and the damper device must be matched to the characteristics of the internal combustion engine. Even if only the characteristics of either the pump or the damper device are changed, the high-pressure pump integrated with the damper device must be designed as a new model. There was a problem that increased the number of models depending on each characteristic, causing cost increase. The object of the present invention is to solve each of these problems.

  In order to solve the above problems, the present invention provides a fuel pressure control system for an internal combustion engine comprising a sealed housing in which a fuel chamber is formed and a fuel pressure pulsation absorbing member provided in the fuel chamber. In the pulsation reducing device, the housing includes first and second members made of a metal plate, and the first member extends radially outward from the entire circumference of the first cup-shaped portion and the outer peripheral edge on the opening side. An annular contact portion formed between the first and second members, the second member being formed by press working in a shape comprising a flange portion, with the entire periphery of the peripheral portion being in contact with the first flange portion. By irradiating a laser beam from the direction orthogonal to the contact portion of both members over the entire circumference of the member, the two members are locally melted to a depth exceeding the contact surface between the two members so that the two members are integrated. And liquid-tight A fuel pressure pulsation comprising a connecting pipe connecting the internal fuel chamber to a connecting line of a fuel injection system for an internal combustion engine through a wall surface of the housing. A reduction device is provided.

  In the fuel pressure pulsation reducing device configured as described above, the housing is composed of first and second members made of a metal plate, and the first member is the first cup-shaped portion and the entire outer peripheral edge on the opening side thereof. The second member is formed by press working in a shape including a first flange portion extending radially outward from the periphery, and the second member is in contact with the entire periphery of the peripheral portion overlapping the first flange portion. By irradiating a laser beam from the direction orthogonal to the contact portion of both members over the entire circumference of the annular contact portion formed between the two members, the members are locally moved to a depth exceeding the contact surface between the two members. The two members are integrally and liquid-tightly welded together to form a housing having a fuel chamber therein, and the first and second members are locally heated and melted at the front end portions of the portions. Is scattered in the direction of laser beam irradiation However, the scattering direction is a direction perpendicular to the annular contact surface formed between the first flange portion and the peripheral edge portion of both members and passes outside the fuel chamber. Even if a part of the member becomes fine spatter and is scattered in the laser beam irradiation direction, such spatter does not enter the fuel chamber and cause clogging of the fuel injection valve. The housing is connected to the connecting line of the fuel injection system for the internal combustion engine by a connecting pipe provided through the wall surface. Therefore, the fuel pressure pulsation reducing device according to the present invention is produced as a single component, It can be incorporated into any type of internal combustion engine that requires it without affecting other components. As a result, when the number of internal combustion engines to be produced is large, it is possible to prevent the number of types of parts from increasing compared to the number of models, thereby reducing the cost increase factor.

  In the fuel pressure pulsation reducing device configured as described above, the second member is shallower than the first cup-shaped portion of the first member by press working and can be inserted into the first cup-shaped portion. The second member is formed into a shape including a second flange portion that extends radially outward from the entire periphery of the periphery on the opening side, and the second cup has a second cup-shaped portion as a first cup of the first member. The second flange portion is overlapped with and abutted on the first flange portion in either of the state inserted into the shape portion and the state in which the second cup shape portion protrudes from the first cup shape portion in the opposite direction. It is preferable that the welding is integrally and liquid-tightly welded by laser beam welding. In this case, even when the same first member and the same second member are used in combination, the second cup-shaped portion of the second member is inserted into the first cup-shaped portion of the first member; When the second cup-shaped portion protrudes from the first cup-shaped portion in the opposite direction, the height of the fuel chamber formed in the housing is larger in the latter case. Therefore, when the same pulsation damper is used, the number of pulsation dampers can be increased in the latter case, so two types of fuel pressures having different pulsation absorption performance using the same combination of members are used. Thus, a fuel pressure pulsation reducing device with high pulsation absorption performance can be obtained without increasing the number of parts. In addition, the first and second members constituting the housing are both press-molded products, and the wall thickness can be significantly reduced as compared with a conventional damper housing formed integrally with a pump housing of a die-cast product. Therefore, the housing itself also has a certain level of pulsation absorbing function, which can improve the pulsation absorbing performance of the pulsation reducing device.

  In the fuel pressure pulsation reducing device configured as described above, it is preferable that the second cup-shaped portion of the second member has a truncated cone shape with its opening side widened. In this case, the pulsation absorbing function can be obtained also by the truncated cone-shaped inclined surface of the second cup-shaped portion, so that the pulsation absorbing performance of the fuel pressure pulsation reducing device can be enhanced.

  In the fuel pressure pulsation reducing device configured as described above, the pressure pulsation absorbing member includes at least one of the first and second diaphragm members each made of a metal plate thinner than the thickness of the metal plate of the housing. At least one pulsation damper that is pressed into a cup shape shallower than the member, and that the outer peripheral edge portions of the first and second diaphragm members are in contact with each other and are hermetically welded to form a sealed space inside. Preferably there is. In this case, since each diaphragm member constituting the pulsation damper is a thin metal plate, there is no risk of swelling and deterioration with respect to any fuel, and high durability can be obtained.

  In the fuel pressure pulsation reducing device configured as described above, the pressure pulsation absorbing member presses the third diaphragm member made of a metal plate thinner than the metal plate of the housing into a cup shape shallower than the first member. Preferably, the outer periphery of the third diaphragm member is in contact with the flat inner surface of the central portion of at least one of the first and second members to be liquid-tightly fixed. Even in this case, since the third diaphragm member is a metal plate, there is no risk of swelling and deterioration with respect to any fuel, and high durability can be obtained.

  In the fuel pressure pulsation reducing device configured as described above, the section excluding the peripheral edge of the second member has a corrugated cross section with a plane including the central axis of the second member, and is concentric with the central axis as the center. It is preferable to bend so that In this case, since the elongation rigidity in the radial direction of each part of the second member is reduced and the pressure receiving area is increased, the pulsation absorbing performance by the second member can be further enhanced.

It is a top view which shows the whole structure of 1st Embodiment of the pulsation reduction apparatus of the fuel pressure by this invention. FIG. 2 is a cross-sectional view taken along line 2-C-2 in FIG. It is sectional drawing equivalent to FIG. 2 of 2nd Embodiment in the pulsation reduction device of the fuel pressure by this invention. It is sectional drawing equivalent to FIG. 2 of 3rd Embodiment in the pulsation reduction device of the fuel pressure by this invention. It is sectional drawing equivalent to FIG. 2 of 4th Embodiment in the pulsation reduction apparatus of the fuel pressure by this invention. It is sectional drawing which shows an example in the fuel pressure pulsation reduction apparatus by a prior art.

  Embodiments of a fuel pressure pulsation reducing device according to the present invention will be described below with reference to the accompanying drawings. First, the fuel pressure pulsation reducing apparatus 10 according to the first embodiment is formed by a housing 11 having two connecting pipes 16 and a mounting bracket 17, respectively, as shown in FIGS. 1 and 2, and the housing 11. The pressure pulsation absorbing member D is provided in the fuel chamber 15.

  The fuel pressure pulsation absorbing member D of the first embodiment is substantially the same as the pulsation damper 20 described in FIG. 6 in the description of the prior art, and a thin metal plate is pressed into a circular shallow cup shape. The flange portions 21a and 22a formed on the outer circumferences of the two first and second diaphragm members 21 and 22 (hereinafter simply referred to as diaphragm members 21 and 22) are overlapped, and the entire circumference is laser beam welded or the like. To form a sealed space inside. In the illustrated embodiment, both of the two diaphragm members 21 and 22 are pressed into the same shallow cup shape, and the flange portions 21a and 22a are formed on the outer circumferences. However, either one of the two diaphragm members is used. 21 is pressed into a cup shape having a flange portion 21 a on the outer periphery, and the other diaphragm member 22 is a disk having the same diameter as the outer diameter of the flange portion 21 a, and the outer peripheral edge portion of the first diaphragm member 21 is It is good also as what overlapped with the flange part 21a and welded liquid-tightly by laser beam welding etc. over the perimeter, and formed the space sealed inside.

  As shown in FIGS. 1 and 2, the housing 11 according to the first embodiment is composed of first and second members 12 and 13 formed by press working, and the members 12 and 13 are diaphragm members 21 and 13, respectively. A metal plate that is slightly thicker than the thin metal plate used for 22 is used as a material. The first member 12 is formed by pressing a metal plate material as described above, and the first cup-shaped portion 12a having a bottomed cylindrical shape that is shallower than the diameter, and outward from the entire circumference of the outer periphery on the opening side. The first flange portion 12b having a constant width extending in the shape is formed into a shape. A shallow circular protrusion 12d is formed on the bottom wall of the first cup-shaped portion 12a, and the outer peripheral wall of the first cup-shaped portion 12a has a small inward flange at a predetermined angle in the circumferential direction. Two connecting holes 12c are formed by burring or the like. The shape of the first cup-shaped portion 12a is not limited to a cylindrical shape, and may be any regular polygonal cylindrical shape such as a square having a rounded corner.

  The two connecting pipes 16 connected to each connecting hole 12c have the same shape, and one end of the elongated tube material is rounded inward, and a ring is formed at a position slightly deviated toward the one end side in the longitudinal direction and on the outer periphery of the other end part. A stop projection 16a and a positioning projection 16b are formed. The two connection pipes 16 are inserted into the respective connecting holes 12c from the outside, and the positioning protrusions 16b are brought into contact with the surface of the first cup-shaped part 12a to position the first connecting member. 12 is liquid-tightly brazed and fixed.

  The first member 12 is provided with two mounting brackets 17 having the same shape for mounting the fuel pressure pulsation reducing device 10 in the vicinity of the internal combustion engine. Each mounting bracket 17 is formed by bending a metal plate similar to the material of the first and second members 12 and 13 into a L-shaped cross section composed of a long side portion and a short side portion by pressing. Each mounting bracket 17 is curved in the shape of a short side in a plan view shown in FIG. 1 into an arc shape that can contact the outer surface of the outer peripheral wall of the first cup-shaped portion 12a of the first member 12 without a gap. A mounting hole 17a is formed at the tip of the part. The two mounting brackets 17 are brazed and fixed with their short sides abutting against the outer peripheral wall of the first cup-shaped portion 12a at a predetermined angle in the circumferential direction.

  The second member 13 includes a second cup-shaped portion 13a that is shallower than the first cup-shaped portion 12a of the first member 12 and can be inserted into the first cup-shaped portion 12a by pressing, and the entire peripheral edge on the opening side thereof. The outer surface of the second flange 13b is formed in the shape of the second flange 13b that extends radially outward from the circumference and becomes the peripheral edge of the second member 13. The outer diameter of the second flange 13b is the outer diameter of the first flange 12b. Is the same. The second cup-shaped portion 13a of the second member 13 of the first embodiment has a truncated cone shape whose height is slightly less than half the height of the first cup-shaped portion 12a and whose opening side is widened. As shown in FIG. 2, the second member 13 has a second cup-shaped portion 13a inserted into the first cup-shaped portion 12a of the first member 12 or in the opposite direction. As the state in which the portion 13a protrudes from the first cup-shaped portion 12a (see FIG. 3 described later), the second flange portion 13b can be brought into contact with the first flange portion 12b.

  As shown in FIGS. 1 and 2, one pulsation damper 20 is held in the first member 12 by an attachment member 23. The mounting member 23 has a circularly curved shape with a part cut off, and is elastically held on the inner surface of the first cup-shaped portion 12a of the first member 12, and the circumference of the belt plate 23a The holding portion 23b has two holding pieces integrally formed at three locations in the direction. The pulsation damper 20 is held between the holding pieces of the holding portions 23b with the flange portions 21a and 22a sandwiched between them (see FIG. 2). As a result, the first cup-shaped portion 12a is held. In this state, the second flange portion 13b is set to the first flange portion of the first member 12 so that the second cup portion 13a is inserted into the first cup-shaped portion 12a of the first member 12. A housing 11 having a fuel chamber 15 in which the pulsation damper 20 is accommodated is formed by being in contact with the liquid layer 12b and being liquid-tightly welded. As shown by an arrow A in FIG. 2, the welding is performed by irradiating the second flange portion 13b with a laser beam from the lower side perpendicular to the second flange portion 13b to a depth slightly exceeding the thickness of the second flange portion 13b. 13b is melted locally, and the irradiation position of the laser beam is moved along the entire circumference of the circular line 14 near the center in the width direction of the annular contact portion formed between the flange portions 12b and 13b. By doing. In this case, the laser beam irradiation can be performed from the upper side perpendicular to the first flange portion 12b.

  In the second embodiment shown in FIG. 3, the first and second members 12 and 13 that are exactly the same as those in the first embodiment are used, and the second member 13 is opposite to that shown in FIG. The second flange portion 13b is overlapped with the first flange portion 12b so as to protrude from the first cup-shaped portion 12a so that the two cup-shaped portions 13a protrude from the first cup-shaped portion 12a. What is necessary is just to perform the welding coupling | bonding of both the flange parts 12b and 13b in this case similarly to having demonstrated in FIG. The height of the space formed between the first and second members 12 and 13 welded to each other and serving as the fuel chamber 15 is about the height of the first embodiment shown in FIG. 2 in this second embodiment. Doubled. Therefore, if the dimensions of the pulsation damper 20 are the same, the number of pulsation dampers 20 constituting the pressure pulsation absorbing member D is one in the first embodiment shown in FIG. In the second embodiment, since the number can be two, it is possible to obtain a fuel pressure pulsation reducing device having the same outer diameter of the housing 11 as the maximum dimension and a pulsation absorption performance approximately twice as large. That is, according to the second embodiment, it is possible to form the fuel chamber 15 that can accommodate the two pulsation dampers 20 by using the same number of first and second members 12 and 13 that are shared with the first embodiment. Thus, a fuel pressure pulsation reducing device with high pulsation absorption performance can be obtained. The pulsation damper 20 used in the fuel pressure pulsation reducing device of FIG. 3 eliminates the flange portions of the diaphragm members 21 and 22 and increases the outer diameter of the cup-shaped portion of the diaphragm members 21 and 22, so that both diaphragms are used. The opening edge which becomes the outer periphery part of the members 21 and 22 is abutted and welded together by a laser beam or the like to form a sealed space inside. In this way, one pulsation damper 20 Since the volume increases, the pulsation absorption performance can be further enhanced. The attachment member 24 used in this case is provided with holding portions 24b at three locations in the circumferential direction on both sides of the band plate 24a similar to the band plate 23a described above.

  Next, the third embodiment shown in FIG. 4 will be described. In the third embodiment, two pulsation dampers 20 constituting the pressure pulsation absorbing member D have substantially the same structure as that of the first embodiment, and the structure of the housing 11 and the support structure of the pulsation damper 20 are used. Is different from the first and second embodiments. Therefore, these differences will be mainly described.

  In the third embodiment, the first member 12 of the housing 11 is substantially the same as the first member 12 of the first and second embodiments, except that the height is high. The second member 13 is substantially disc-shaped without the second cup-shaped portion 13a, and the annular peripheral edge portion 13b and the central flat portion 13c corresponding to the second flange portion are substantially the same height and are outside the central flat portion 13c. Subsequently, a downward projecting portion 13d having an annular bottom flat surface is formed, and an upward projecting portion 13e having a mountain-shaped cross section is formed between the downward projecting portion 13d and the second flange portion 13b. Accordingly, the portion of the second member 13 excluding the peripheral edge portion 13b is bent so that the cross section of the plane including the central axis C is concentric with the central axis C of the second member 13 as a waveform. Note that the thickness of the second member 13 is slightly smaller than that of the first member 12.

  The elastic mounting member 25 that is a support structure of the pulsation damper 20 includes a frame 25a that has a passage through which fuel passes on the upper surface and the lower surface and supports the pulsation damper 20, and the center of the upper surface and the lower surface of the frame 25a. The four leg portions 25b are provided integrally with each other. Each of the four leg portions 25b is bent so as to be separated from the frame 25a, and each tip portion is bent so as to be parallel to the central portion. The pulsation damper 20 supported by the frame 25a is overlapped with flange portions 21a and 22a formed on the outer peripheries of the respective diaphragm members 21 and 22, as described in the description of the prior art. It has a space sealed in a liquid-tight manner by welding or the like.

  In the third embodiment, as shown in FIG. 4, the two pulsation dampers 20 are stacked in two upper and lower stages by a frame 25a, and the distal end portions of the leg portions 25b of the elastic mounting member 25 that are in contact with each other. Are integrally connected to each other by, for example, bending caulking or the like, thereby configuring the pressure pulsation absorbing member D of the third embodiment. The two pulsation dampers 20 thus connected are placed on the second member 13 so that the tips of the lower leg portions 25b abut on the annular bottom flat surface of the downward projecting portion 13d. The first member 12 provided with the connecting pipe 16 and the mounting bracket 17 is covered, the first flange portion 12b of the first member 12 is brought into contact with the peripheral edge portion 13b of the second member 13, and the above-described laser beam welding is performed. The housing 11 having the fuel chamber 15 in which the pulsation damper 20 is housed is formed by being liquid-tightly welded. The tip of each leg portion 25b that is the uppermost portion contacts the inner surface of the protruding portion 12d of the first member 12 before the first flange portion 12b of the first member 12 contacts the peripheral edge portion 13b of the second member 13. Therefore, in a state where the first member 12 and the second member 13 are welded, each elastic mounting member 25 is elastically bent, and each pulsation damper 20 is elastically held, and the protruding portion 12d and the downward protruding portion 13d. Therefore, the movement in the radial direction is also restricted.

  Next, the fourth embodiment shown in FIG. 5 will be described. In the fourth embodiment, the shapes of the third diaphragm member 26 and the second member 13 constituting the pressure pulsation absorbing member D are different from those of the first embodiment. Therefore, these differences will be mainly described.

  In the fourth embodiment, the second member 13 of the housing 11 has a flat disk shape, and its thickness is somewhat smaller than that of the first member 12. The pressure pulsation absorbing member D is formed by pressing a metal plate into a cup-shaped portion 26a that is shallower than the first cup-shaped portion 12a of the housing 11 and a third flange portion 26b that protrudes radially outward from the outer periphery thereof. Two third diaphragm members 26 formed in the above are used. Each third diaphragm member abuts the third flange portion 26b on the flat inner surfaces of the central portions of the first and second members 12 and 13 of the housing 11, and is liquid-tightly fixed by laser beam welding or the like. In addition, a sealed space is formed between the second members 12 and 13.

  According to each embodiment mentioned above, the 1st member 12 and the 2nd member 13 which constitute housing 11 contact the 1st flange part 12b, the 2nd flange part 13b is piled up, and contact with the 2nd flange part 13b. On the other hand, a laser beam is irradiated from the lower side perpendicular to each other, and both the flange portions 12b and 13b are locally melted to a depth slightly exceeding the thickness of the second flange portion 13b, so that both the members 12 and 13 are integrally and liquid. A housing 11 having a fuel chamber 15 therein is formed by tight welding. At the time of this welding, a force to be scattered in the irradiation direction of the laser beam is applied to the tip of the locally heated and melted portions of both flange portions 12b and 13b. Since the members 12 and 13 pass through the outside of the fuel chamber 15 in a direction perpendicular to the contact surfaces of the members 12 and 13 with the flange portions 12b and 13b, a part of the melted flange portions 12b and 13b becomes fine spatter. Even if scattered in the laser beam irradiation direction, such spatter does not enter the fuel chamber 15 and cause a clogging of the fuel injection valve.

  In the fuel pressure pulsation reducing device 10 according to each of the above-described embodiments, the return in the fuel injection system for an internal combustion engine in which the control of the fuel injection amount and the injection timing is controlled by returning from the plunger pump to the fuel supply passage side. It may be attached in the middle of a relatively low-pressure connection line such as a pipe line, or a connection line for directly supplying fuel from a high-pressure pump to a delivery pipe provided with a fuel injection valve having an electromagnetic valve You may attach in the middle.

  In each of the above-described embodiments, the first and second members constituting the housing 11 are both press-formed products, and are thicker than the conventional damper housing formed integrally with the pump housing of the die cast product. Since the thickness can be significantly reduced, the housing 11 itself has a certain level of pulsation absorbing function, thereby improving the pulsation absorbing performance of the fuel pressure pulsation reducing device.

  In the first and second embodiments described above, the second member 13 is shallower than the first cup-shaped portion 12a of the first member 12 by press working and can be inserted into the first cup-shaped portion 12a. The second member 13 has a first cup-shaped portion 13a that is a first cup portion 13a. The second flange portion 13b is inserted into the first cup-shaped portion 12a of the member 12 and the second cup-shaped portion 13a is protruded from the first cup-shaped portion 12a in the opposite direction. The housing 11 can be formed by overlapping and abutting on the first flange portion 12b and integrally joining by welding with a laser beam.

  In this way, even when the same first member 12 and the same second member 13 are used in combination, the second cup-shaped portion 13a of the second member 13 is in the first cup-shaped portion 12a of the first member 12. When the second cup-shaped portion 13a protrudes from the first cup-shaped portion 12a in the opposite direction, the height of the fuel chamber 15 formed in the housing 11 is the latter. Is bigger. Therefore, when the same pulsation damper 20 is used, the number of pulsation dampers 20 that can be accommodated in the fuel chamber 15 can be increased in the latter case, and pulsation absorption can be achieved by using the same combination of members. Two types of fuel pressure pulsation reducing devices having different performances can be produced. Thus, according to what increased the number of pulsation dampers, the fuel pressure pulsation reduction apparatus with high pulsation absorption performance can be obtained, without increasing a number of parts.

  However, the present invention is not limited to this, and the second member 13 is a simple disk having the same outer diameter as that of the first cup-shaped portion 12a, and the entire peripheral portion of the second member 13 is placed on the first flange portion 12b. It is also possible to form the housing 11 by overlapping the circumferences and contacting them together by welding with a laser beam. Even in this case, the above-described high durability can be obtained, the clogging of the fuel injection valve can be prevented, and the pulsation absorbing function of the fuel pressure pulsation reducing device can be enhanced by the pulsation absorbing function of the housing 11 itself. Each effect can be obtained.

  In the first and second embodiments described above, the second cup-shaped portion 13a has a truncated cone shape whose opening side is widened. By doing in this way, a pulsation absorption function can be obtained also by the truncated cone-shaped inclined surface of the second cup-shaped portion 13a, so that the pulsation absorption performance of the fuel pressure pulsation reducing device can be enhanced.

  In the third embodiment described above, the second member 13 has a substantially disk shape without the second cup-shaped portion 13a, and the annular peripheral edge portion 13b and the central flat portion 13c corresponding to the second flange portion have substantially the same height. A downward projecting portion 13d having an annular bottom flat surface is formed on the outer side of the central flat portion 13c, and an upward projecting portion 13e having a mountain shape is formed between the lower projecting portion 13d and the second flange portion 13b. ing. The portion of the second member 13 excluding the peripheral edge is bent so that the cross section of the plane including the central axis C of the second member 13 is corrugated and is concentric with the central axis C as the center. Thereby, since the elongation rigidity in the radial direction of each part of the second member 13 is reduced and the pressure receiving area is increased, the pulsation absorbing performance by the second member 13 can be further enhanced.

  According to the first to third embodiments described above, at least one of the pulsation dampers 20 provided in the fuel chamber 15 of the housing 11 and performing the pulsation absorbing action is pressed into a cup shape as described above, It consists of two diaphragm members 21 and 22 in which the entire circumference of the peripheral part is in contact with each other and is hermetically welded to form a sealed space inside. The two diaphragm members 21 and 22 are both made of thin metal plates. High durability against any fuel.

  In the fourth embodiment described above, the pressure pulsation absorbing member D presses the third diaphragm member 26 made of a metal plate thinner than the thickness of the metal plate of the housing 11 into a cup shape shallower than the first member 12. The entire circumference of the outer peripheral edge of the three diaphragm member 26 was brought into contact with the flat inner surfaces of the central portions of the first and second members 12 and 13 and fixed in a liquid-tight manner. Even in this case, like the pulsation damper 20 of the first to third embodiments described above, the third diaphragm member 26 is high because there is no risk of swelling and deterioration with respect to any fuel. Durability is obtained. In addition, even if the third diaphragm member is in contact with the flat inner surface at the center of the first member 12 and the second member 13 of the first and second embodiments described above, An effect can be obtained.

  As described in Patent Document 2, in the high-pressure pump integrated with the damper device, the characteristics of both the pump and the damper device must be matched to the characteristics of the internal combustion engine, and the characteristics of either the pump or the damper device are changed. However, the damper device integrated high-pressure pump had to be designed as a new model. For this reason, the high-pressure pump integrated with the damper device has a large number of models depending on the characteristics of the pump or the damper device, which causes a problem of increasing costs. However, the fuel pressure pulsation reducing device 10 according to the present invention can be produced as a single component and incorporated into any type of internal combustion engine that requires it without affecting other components. As a result, when the number of internal combustion engines to be produced is large, it is possible to prevent the number of types of parts from increasing compared to the number of models, and to reduce the cost increase factor.

  DESCRIPTION OF SYMBOLS 10 ... Fuel pressure pulsation reduction apparatus, 11 ... Housing, 12 ... 1st member, 12a ... 1st cup-shaped part, 12b ... 1st flange part, 13 ... 2nd member, 13a ... 2nd cup-shaped part, 13b ... 2nd flange part (peripheral part), 15 ... fuel chamber, 16 ... connecting pipe, 20 ... pulsation damper, 21 ... 1st diaphragm member, 22 ... 2nd diaphragm member, 26 ... 3rd diaphragm member, D ... pressure pulsation Absorbing member.

Claims (6)

In a fuel pressure pulsation reducing device in a fuel injection system for an internal combustion engine comprising a sealed housing in which a fuel chamber is formed, and a fuel pressure pulsation absorbing member provided in the fuel chamber,
The housing is composed of first and second members made of a metal plate,
The first member is formed by press working in a shape including a first cup-shaped portion and a first flange portion extending radially outward from the entire outer peripheral edge on the opening side thereof,
The second member is in contact with the entire circumference of the peripheral portion overlapping the first flange portion,
A contact surface between the two members by irradiating a laser beam from a direction orthogonal to the contact portions of the two members over the entire circumference of the annular contact portion formed between the first and second members. Both of these members are locally melted to a depth exceeding 50 mm, and the two members are integrally and liquid-tightly welded to form a housing having the fuel chamber therein,
The fuel pressure pulsation reducing device characterized in that the housing includes a connection pipe that penetrates the wall surface and connects the fuel chamber in the housing to a connection pipe of the fuel injection system for the internal combustion engine.   2. The fuel pressure pulsation reducing device according to claim 1, wherein the second member is shallower than the first cup-shaped portion of the first member by press working and can be inserted into the first cup-shaped portion. The second member is formed into a shape including a second flange portion serving as the peripheral portion extending radially outward from the entire periphery of the peripheral portion serving as the opening side thereof, and the second cup-shaped portion of the second member is the first member. The second flange portion is connected to the first flange in either the state inserted into the first cup-shaped portion or the state in which the second cup-shaped portion protrudes from the first cup-shaped portion in the opposite direction. An apparatus for reducing pulsation of fuel pressure, wherein the fuel pressure pulsation reducing apparatus is integrally and liquid-tightly welded by welding with the laser beam.   3. The fuel pressure pulsation reducing device according to claim 2, wherein the second cup-shaped portion of the second member has a truncated cone shape whose opening side is widened. 4.   4. The fuel pressure pulsation reducing device according to claim 1, wherein each of the pressure pulsation absorbing members is made of a metal plate thinner than a thickness of the metal plate of the housing. At least one of the diaphragm members is pressed into a cup shape that is shallower than the first member, and the entire circumferences of the outer peripheral edge portions of the first and second diaphragm members are brought into contact with each other to be hermetically welded to form a sealed space inside. A fuel pressure pulsation reducing device comprising at least one pulsation damper formed.   4. The fuel pressure pulsation reducing device according to claim 1, wherein the pressure pulsation absorbing member includes a third diaphragm member made of a metal plate thinner than a metal plate thickness of the housing. Pressed into a cup shape shallower than one member, and the entire circumference of the outer peripheral edge of the third diaphragm member is in contact with the flat inner surface of the central portion of at least one of the first and second members to be liquid-tight A fuel pressure pulsation reducing device characterized by being fixed.   6. The fuel pressure pulsation reducing device according to claim 1, wherein a portion of the second member excluding the peripheral edge portion is corrugated by a plane including a central axis of the second member. A fuel pressure pulsation reducing device characterized by being bent so as to be concentric with the central axis as a center.

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