Method for manufacturing housing of injector, and injector

Abstract

The present invention provides a method for manufacturing a housing of an injector for the purpose of improving the durability of the injector, and an injector with improved durability. This method for manufacturing a housing (2) of an injector (1) includes a step for obtaining a housing (2) by making a hole along a central axis with respect to an injector body (2B) obtained from a base material. An inlet part (3) is attached at the position of a first axial range (A1) and a first circumferential range (α) in the injector body (2B). In each of the first circumferential range (α) and a second circumferential range, the injector body (2B) has a first width, being a width in the radial direction, that is greater in the first axial range (A1) than in a second axial range other than the first axial range (A1). Provided that the central axis of the injector body (2B) is the z-axis in an xyz space and the radial direction proceeding from the central axis to the center of the first circumferential range (α) is the x direction, the second circumferential range is positioned opposite the first circumferential range with the y-axis therebetween.

Description

[0001] [Document name] Statement

[0002] [Title of invention] Manufacturing method of injector housing, and injector

[0003] [Technical Field]

[0004] [. 0 0 1] The present invention relates to a method for manufacturing an injector housing, and to an injector.

[0005] [Background technology]

[0006]

[002] Conventionally, injectors for various applications have been known. For example, in the field of automotive technology, an injector for injecting fuel from a common rail into an internal combustion engine is known (see, for example, Patent Document 1).

[0007] [〇 0 0 3] An injector comprises a nozzle body that forms a flow path for the fuel or other target to be injected, and a housing that forms the outer shell of the injector. The housing is provided with an inlet that guides the target to be injected from a common rail or the like into the injector. The inlet forms a flow path for the target to be injected, and the housing forms a hole that connects to the flow path in the inlet and serves as the flow path for the target to be injected. The hole communicates with the space inside the housing in which a valve or the like is located. The target to be injected that flows into the injector via the inlet is ejected to the outside through the flow path defined by the nozzle body.

[0008] [0 0 0 4] When a high-pressure injection target is circulated through the injector, the housing must have high strength. Housings that require such high strength are manufactured from a base material whose main component is a high-strength first substance. The first substance is, for example, iron. However, manufacturing the housing using only the first substance can be difficult. Therefore, to facilitate manufacturing of the housing, a second substance such as lead or sulfide is often added to the base material. The manufactured housing often contains the second substance. Here, the second substance has a lower melting point and lower strength than the first substance. Therefore, to increase the strength of the housing, it is desirable that the amount of the second substance in the housing is small and that the second substance is finely dispersed.

[0009] [Prior art documents]

[0010] [Patent documents]

[0011]

〇 0 0 5

[0012] [Patent Document 1] Japanese Patent Application Laid-Open No. 2021-060013

[0013] Summary of the Invention

[0014] [Problem to be solved by the invention]

[0015] [0 0 6] However, depending on the manufacturing process of the housing, the amount of the second substance may be large in a specific part of the housing. This may result in high stress acting on that specific part. For example, high stress may act on the peripheral part of the outlet of the hole in the housing that connects to the flow path in the inlet portion. Such a specific part is prone to significant strength reduction, which may result in early failure of the injector.

[0016]

[0007] The present invention has been made to solve the above problems, and aims to provide a method for manufacturing a housing for an injector in order to improve the durability of the injector, and an injector with improved durability.

[0017] [Means for solving the problem]

[0018]

[0008] A method for manufacturing a housing (2) of an injector (1) according to one aspect of the present invention includes the steps of: melting and extruding a base material in which a second material having a melting point lower than that of a first material that is a main component of the housing (1) is added; obtaining a bar material (2A) by melting and extruding the base material; forging the bar material (2A) to obtain an injector body (2B); and drilling a hole (20) in the injector body (2B) obtained from the bar material (2A) along an axial direction that is a direction of a central axis of the injector body (2B) obtained from the bar material (2A), to obtain the housing (2). In the injector body (2B), a first width that is a width in a radial direction from the central axis is set within a predetermined first axial range (A1) in the axial direction in a first circumferential range (a) and a second circumferential range (b) in a circumferential direction. and a second axial range other than the first axial range (A1), and an inlet portion (3) that introduces the injection target into the housing (2) is attached at a position in the first axial range (a) and the first axial range (A1), so that the first width in the first axial range (a) and the first axial range (A1) is larger than the first width in the second axial range, and when the central axis is defined as the z-axis in the xyz space and the radial direction from the central axis toward the center of the first axial range (a) is defined as the x-direction, the second axial range is located on either side of the first axial range (a), and the first width in the second axial range and the first axial range (A1) is larger than the first width in the second axial range.

[0019]

[0009] An injector (1) according to one aspect of the present invention includes a housing (2) forming an outer shell, and an inlet (3) for introducing an injection target into the housing (2), wherein the housing (2) is obtained by melting and forging a base material in which a second material having a melting point lower than that of a first material is added to a first material, and the base material is formed by forging the melted material, and a first distance, which is a distance from a central axis of the housing (2) to an end of the housing (2) in a radial direction, in each of a first circumferential range (a) and a second circumferential range in a circumferential direction of the housing (2), differs between a predetermined first axial range (A1) in an axial direction that is the direction of the central axis and a second axial range other than the first axial range (A1), and a first distance, which is a distance from a central axis of the housing (2) to an end of the housing (2) in a radial direction, in the first circumferential range (a) and the first axial range (A1), differs between the first circumferential range (a) and the first axial range (A1). The inlet portion (3) is attached at a position in (A1), and the first distance in the first circumferential range (a) and the first axis range (A1) is longer than the first distance in the second axis range, and when the central axis is defined as the z-axis in xyz space and the radial direction from the central axis toward the center of the first circumferential range (a) is defined as the x-direction, the second circumferential range is located on either side of the first circumferential range (a) with respect to the y-axis, and the first distance in the second circumferential range and the first axis range (A1) is longer than the distance in the second axis range.

[0020] [Effects of the Invention]

[0021]

[0010] In the injector housing manufacturing method and injector according to the present invention, the first width in the first axial range is larger than the first width in the second axial range not only in the first circumferential range of the injector body but also in the second circumferential range. The first distance in the first axial range is larger than the first distance in the second axial range not only in the first circumferential range of the housing but also in the second circumferential range. This makes it possible to prevent the second material from being distributed excessively in the first axial range and on the side of the first circumferential range of the housing during the housing manufacturing process, and to prevent a decrease in strength of the housing in areas where high stress acts. This prevents a significant decrease in strength of the areas where high stress acts during injector operation, resulting in improved durability of the injector.

[0022] [Brief explanation of the drawings]

[0023] [ 0 0 1 1 ]

[0024] [Figure 1] A diagram illustrating a cross section of an injector in an embodiment.

[0025] [Figure 2] A diagram schematically illustrating an initial step of a manufacturing method for an injector housing according to an embodiment.

[0026] [Figure 3] A diagram illustrating a schematic example of the distribution of a second substance in a bar material according to an embodiment.

[0027] [Figure 4] A diagram schematically showing a portion of the side surface of an injector body according to a comparative example and the distribution of a second substance.

[0028] FIG. 5 is a diagram schematically illustrating a cross section along the xy plane of an injector body according to a comparative example.

[0029] [Figure 6] A diagram schematically showing a portion of a cross section of a housing related to a comparative example.

[0030] [Figure 7] A diagram schematically illustrating a part of the side surface of the injector body in the embodiment and the distribution of the second substance.

[0031] FIG. 8 is a diagram schematically illustrating an example of a cross section of an injector body according to an embodiment taken along an xy plane.

[0032] [Figure 9] A diagram schematically showing another example of a cross section along the xy plane of the injector body according to the embodiment.

[0033] [Figure io] A diagram schematically illustrating a portion of a cross section of a housing in an embodiment.

[0034] DETAILED DESCRIPTION OF THE INVENTION

[0035]

[0012] Below, a method for manufacturing an injector housing and an injector according to an embodiment will be described with reference to the drawings. Note that the present invention is not limited to the following embodiments and can be modified in various ways without departing from the spirit of the present invention. Furthermore, the present invention includes all possible combinations of configurations shown in the following embodiments. Furthermore, the injectors, housings, etc. shown in the drawings are merely examples of the injectors, housings, etc. of the present invention, and the present invention is not limited to the drawings. Furthermore, in each drawing, parts with the same reference numerals are the same or corresponding parts, and this applies throughout the entire specification. Note that the size relationships between components in each drawing are not limited to those shown in the drawings.

[0036]

[0013] Fig. 1 is a diagram illustrating a cross section of an injector 1 according to an embodiment. In this embodiment, the injection target of the injector 1 is fuel, and the injector 1 is a fuel injection valve. The fuel injection valve is a component of an accumulator-type fuel injection control device. In addition to the fuel injection valve, the accumulator-type fuel injection control device has a supply pump, a common rail, and the like. The supply pump pressurizes fuel from a fuel tank, and the common rail stores the fuel pressurized by the supply pump. The fuel injection valve injects fuel from the common rail into the cylinders of an internal combustion engine.

[0037]

[0014] As shown in Fig. 1, injector 1 includes housing 2, inlet portion 3, nozzle body 4, nozzle needle 5, nozzle spring 6, nozzle nut 7, valve 8, and pressure control portion 9.

[0015] Housing 2 forms the outer shell of injector 1. That is, housing 2 has a hole 20 extending along its central axis, and components such as valve 8 are housed inside hole 20. In this embodiment, the central axis of hole 20 coincides with the central axis of housing 2. In Fig. 1, part of the central axis is indicated by a dashed line.

[0038]

[0016] An inlet portion 3 is provided in a first circumferential range and a first axial range of the housing 2. Here, the first circumferential range refers to a predetermined range in the circumferential direction of the housing 2, and the first axial range refers to a predetermined range in the axial direction of the housing 2. The axial direction is the direction of the central axis of the housing 2. Hereinafter, the central axis of the housing 2 is defined as the z-axis in the xyz space, and the radial direction from the central axis toward the center of the first circumferential range is defined as the x-direction, i.e., the positive direction of the x-axis.

[0039]

[0017] A first flow passage 30 is formed in the inlet portion 3 to introduce fuel from a common rail (not shown) into the housing 2. A second flow passage 21 is formed in a first circumferential range and a first axial range of the housing 2. The second flow passage 21 communicates with the first flow passage 30 and distributes fuel from the first flow passage 30 into the housing 2.

[0040]

[0018] A nozzle body 4 is fastened by a nozzle nut 7 to the end of the housing 2 in the direction along the central axis. The nozzle body 4 is disposed so that its central axis coincides with the central axis of the housing 2. In the following, the positive direction of the z axis is defined as the direction from the nozzle body 4 toward the housing 2 along the central axis.

[0041] Nozzle body 4 defines a part of the fuel flow path. Nozzle body 4 houses nozzle needle 5 therein and has fuel injection hole 40 formed at the end on the negative side of the z axis. Nozzle body 4 is provided with seat portion 41 on the inner space side of nozzle body 4, on the periphery of fuel injection hole 40 and at a portion connected to said periphery. Seat portion 41 is for seating the tip of nozzle needle 5.

[0042] Fuel injection hole 40 is closed when the tip of nozzle needle 5 seats on seat portion 41, and is opened when the tip of nozzle needle 5 moves away from seat portion 41. When fuel injection hole 40 is opened, fuel is injected outside injector 1, and when fuel injection hole 40 is closed, fuel injection stops.

[0043]

[0021] A spring chamber 22 is formed in the housing 2, and a nozzle spring 6 is disposed in the spring chamber 22. The nozzle spring 6 biases the nozzle needle 5 toward the seat portion 41.

[0044] A fuel reservoir chamber 42 is formed within the nozzle body 4, and the fuel reservoir chamber 42 communicates with a space that houses the nozzle needle 5. A third flow path 23 is formed in the housing 2 and the nozzle body 4. The third flow path 23 communicates with the first flow path 30 of the inlet portion 3 and allows fuel from the inlet portion 3 to flow into the fuel reservoir chamber 42.

[0045] A pressure-receiving portion 50 is formed in a portion of the nozzle needle 5 located within the fuel sump chamber 42. Pressure in the positive direction of the z-axis from the fuel in the fuel sump chamber 42 acts on the pressure-receiving portion 50. The valve body 80 has a valve body 80 and a valve piston 81. A pressure introducing chamber 24 is formed between the valve body 80 and the housing 2. The valve body 80 is formed in an annular shape in the circumferential direction of the valve body 80 and communicates with a second flow path 21. The valve piston 81 is disposed in the positive direction of the z-axis relative to the nozzle needle 5. A portion of the valve piston 81, including the end of the valve piston 81 in the positive direction of the z-axis, is disposed slidably within a piston chamber 82 of the valve body 8. Hereinafter, the end of the valve piston in the positive direction of the z-axis may also be referred to as a first end 83. A control pressure chamber 84 is formed by the wall of the valve body 80 that forms the piston chamber 82. The control pressure chamber 84 communicates with an introduction side orifice passage 85 formed in the valve body 80, and the orifice passage 85 communicates with the second flow path 21 via the pressure introduction chamber 24. The fuel from the first flow path 30 flows through the second flow path 21, the pressure introducing chamber 24, and the introduction side orifice passage 85 in that order, and then flows into the control pressure chamber 84.

[0046]

[0027] The control pressure chamber 84 is also connected to an opening / closing orifice passage 86 formed in the valve body 80. The opening / closing orifice passage 86 can be opened and closed by a pressure control unit 9.

[0047]

[0028] The pressure control unit 9 is, for example, a solenoid valve, and opens and closes the opening / closing orifice passage 86. In this embodiment, the pressure control unit 9 includes an electromagnet 90, an armature plate 91, an armature bolt 92, an armature guide 93, a spring 94, etc.

[0048]

[0029] The pressure control unit 9 includes a holder 95 having a fuel return path 95a formed therein for returning fuel to a fuel tank (not shown). The holder 95 and the electromagnet 90 are integrated by an electromagnet housing 96. The electromagnet housing 96 is fastened to the housing 2 by a housing nut 97.

[0049]

[0030] When a drive current is supplied to the electromagnet 90 from a control circuit (not shown), the electromagnet 90 generates an electromagnetic force and attracts the armature plate 91.

[0050]

[0031] The armature bolt 92 has a shaft portion 92a and a head portion 92b. The shaft portion 92a is inserted into the armature guide 93. A head portion 92b is provided at one end of the shaft portion 92a, on the positive side of the z axis, i.e., the end on the holder 95 side. The head portion 92b engages with the armature plate 91. A control valve element 98 is provided at the other end of the shaft portion 92a, on the negative side of the z axis, i.e., the end on the control pressure chamber 84 side. The control valve element 98 opens and closes the opening and closing orifice passage 86.

[0051]

[0032] The spring 94 applies a biasing force to the head portion 92b toward the control valve body 98.

[0052]

[0033] The flow of fuel through the injector 1 according to the embodiment will now be described. The fuel that flows from the first flow path 30 of the inlet portion 3 to the third flow path 23 flows into the fuel sump chamber 42. The fuel in the fuel sump chamber 42 applies pressure to the pressure-receiving portion 50 of the nozzle needle 5. The fuel that flows from the first flow path 30 to the second flow path 21 flows into the control pressure chamber 84 via the pressure introducing chamber 24 and the introduction-side orifice passage 85. The fuel in the control pressure chamber 84 applies pressure in the negative direction of the z-axis to the first end 83 of the valve piston 81.

[0053]

[0034] When no drive current is supplied to the electromagnet 90 of the pressure control unit 9, the opening / closing orifice passage 86 is closed by the control valve body 98. In this case, the fuel pressure in the control pressure chamber 84 acts on the nozzle needle 5 via the valve piston 81, and the biasing force of the nozzle spring 6 also acts on the nozzle needle 5. As a result, the nozzle needle 5 seats on the seat portion 41 of the nozzle body 4 and closes the fuel injection hole 40.

[0054]

[0035] Meanwhile, when a drive current is supplied to the electromagnet 90 of the pressure control unit 9, the armature plate 91 is attracted to the electromagnet 90, which causes the armature bolt 92 to move in the positive direction of the z-axis. As the armature bolt 92 moves in the positive direction of the z-axis, the positive pressure of the fuel in the control pressure chamber 84 in the z-axis direction causes the control valve element 98 to open the opening / closing orifice passage 86. As a result, the fuel in the control pressure chamber 84 flows into the pressure control unit 9 via the opening / closing orifice passage 86. Then, the pressure acting on the first end 83 of the valve piston 81 in the control pressure chamber 84 decreases, and the pressure acting on the pressure-receiving portion 50 causes the nozzle needle 5 to move away from the seat portion 41 against the biasing force of the nozzle spring 6. As a result, the fuel injection hole 40 is opened, and fuel is injected outside the injector 1.

[0055]

[0036] When the electromagnet 90 of the pressure control unit 9 is de-energized, the force from the electromagnet 90 no longer acts on the armature plate 91. Then, the armature bolt 92 is returned to the opening / closing orifice passage 86 by the spring 94, and the control valve body 98 closes the opening / closing orifice passage 86. When the opening / closing orifice passage 86 is closed, fuel pressure in the negative direction of the z-axis again acts on the first end 83 of the valve piston 81. The pressure on the first end 83 is transmitted to the nozzle needle 5 via the valve piston 81 and, together with the biasing force of the nozzle spring 6, acts in a direction that seats the nozzle needle 5 on the seat portion 41. This closes the fuel injection hole 40 and stops fuel injection.

[0056]

[0037] High-pressure fuel flows into an injector 1, such as a fuel injection valve, of the above-mentioned accumulator-type fuel injection control device in technical fields such as automobiles. High strength is required for the housing 2 of such an injector 1. For this reason, the housing 2 is manufactured from a base material containing a high-strength first substance, such as iron, as its main component. However, if the base material contains only the first substance, processing can be difficult. Therefore, a second substance, such as lead or a sulfide, which has a lower melting point and lower strength than the first substance, is often added to the base material.

[0057]

[0038] An injector body, which is the basis for the housing 2, is manufactured from such a base material, and a hole 20 is drilled along the axis of the injector body to manufacture the housing 2. When drilling the hole 20 in the injector body, some of the second substance is removed, but the remainder may not be removed and remain in the housing 2. In such cases, the strength of each part of the housing 2 varies depending on the distribution of the second substance in the housing 2. That is, parts that contain a large amount of the second substance have lower strength than parts that do not contain the second substance and parts that contain a small amount of the second substance. If the part that contains a large amount of the second substance is in the flow path of high-pressure fuel, the strength of the housing 2 is likely to decrease significantly, resulting in early damage to the housing 2 and the injector 1.

[0058]

[0039] Specifically, the portion of the housing 2 located at the intersection of the second flow path 21 and the pressure introducing chamber 24 is, for example, 90 0 When high-pressure fuel flows from the second flow path 21 to the pressure introducing chamber 24, high stress acts on the portion located at the intersection. Hereinafter, the portion of the housing 2 on which high stress acts due to the pressure of the fuel injected by the injector 1 may be referred to as the high-stress portion. If the content of the second substance in the high-stress portion is high, the operation of the injector 1 is likely to cause a significant decrease in strength of the high-stress portion. However, if the content of the second substance in the high-stress portion is low, it is possible to suppress the decrease in strength of the high-stress portion due to the operation of the injector 1. The manufacturing method for the housing 2 of the injector 1 according to the embodiment is intended to obtain a housing 2 with a reduced content of the second substance in the high-stress portion, etc. Below, a method for manufacturing the housing 2 of the injector 1 according to the embodiment will be described.

[0059]

[0040] Fig. 2 is a diagram illustrating a schematic example of an initial step in a manufacturing method for the housing 2 of the injector 1 according to the embodiment. The initial step shown in Fig. 2 is the same as that of a conventional method. A base material having a first substance and a second substance added thereto is heated and melted in step S1. In Fig. 2, the melted base material is shown as an area hatched with dashed lines. The melted base material is extruded into a rod shape in step S2. The extruded rod-shaped base material is stretched and cooled in step S3. The base material solidifies upon cooling, and a bar material 2A is obtained. In Fig. 2, the solidified base material is shown as an area hatched with solid lines.

[0060]

[0041] Here, the cooling in step S3 is performed by supplying cold air to the substrate from outside the substrate. At this time, the substrate solidifies from the outside first, but because the second substance has a lower melting point than the first substance, the first substance solidifies first on the outside, and the second substance, which is still liquid, flows toward the central axis of the rod-shaped substrate. As a result, the obtained bar material 2A contains more of the second substance on the central axis side.

[0061]

[0042] Figure 3 is a diagram illustrating a schematic example of the distribution of the second substance in a bar material 2A according to an embodiment. The z direction in Figure 3 corresponds to the z direction in Figure 1, and the r direction corresponds to the radial direction of the bar material 2A. The bar material 2A is obtained from steps S1 to S3 shown in Figure 2. The distribution of the second substance in the bar material 2A shown in Figure 3 is the same as that of the conventional bar material. The thick solid curve in Figure 3 indicates the distribution amount DB of the second substance in the radial direction at the z coordinate position indicated by the two-dot chain line. The z coordinate position indicated by the two-dot chain line is within the first axis range.

[0062]

[0043] As shown in Figure 3, in the bar material 2A, the distribution amount DB of the second substance at the position indicated by the two-dot chain line increases from the radial outside toward the central axis. The distribution amount DB is maximum at the central axis of the bar material 2A. The dot-dash line in Figure 3 is a line that indicates the position in the bar material 2A where the distribution amount DB is maximum in the radial direction, for each z coordinate. As shown in Figure 3, the dot-dash line coincides with the z axis. In other words, the second substance is most distributed at the central axis of the bar material 2A.

[0063]

[0044] Fig. 4 is a diagram schematically showing a portion of the side surface of an injector body 2B according to a comparative example and the distribution of a second substance. The side view of the injector body 2B in Fig. 4 is a diagram viewed along the y direction, and the x direction in Fig. 4 corresponds to the x direction in Fig. 1, and the z direction in Fig. 4 corresponds to the z direction in Fig. 1. The injector body 2B in Fig. 4 is obtained by forging the bar material 2A in Fig. 3. The two-dot chain line in Fig. 4 indicates the same position as the z coordinate position indicated by the two-dot chain line in Fig. 3. The injector body 2B is forged so that the first width in the first axial range A1 and first circumferential range is larger than the first width in the second axial range and larger than the first width in a circumferential range other than the first circumferential range in order to attach the inlet portion 3. The first width is the width in the radial direction from the central axis of the injector body 2B. The second axial range is the range other than the first axial range A1.

[0064]

[0045] The shape of the injector body 2B according to the comparative example shown in Fig. 4 will be described in detail below with reference to Fig. 5. Fig. 5 is a diagram schematically illustrating a cross section of the injector body 2B according to the comparative example along the xy plane. The cross section shown in Fig. 5 is the B-B cross section in Fig. 4, and shows the cross section at the position indicated by the chain double-dashed line. Hereinafter, in the cross section of the injector body 2B along the xy plane at a position in the first axial range A1, the portion on the positive side in the x direction will sometimes be referred to as a first cross-sectional portion CS1, and the portion on the negative side in the x direction will sometimes be referred to as a second cross-sectional portion CS2. Furthermore, of two portions of the injector body 2B that sandwich the y-z plane within all or part of the first axial range A1, the portion on the positive side in the x direction may be referred to as the first portion, and the portion on the negative side in the x direction may be referred to as the second portion. The first cross-sectional portion CS! and the first portion include the first circumferential range a, and the second cross-sectional portion CS2 and the second portion include the second circumferential range. The second circumferential range is a range in the circumferential direction that is located on either side of the first circumferential range a and the y axis, and is all or part of the angle indicated by / 3 in FIG. 5. As shown in FIG. 5, in the comparative example, the area of ​​the first cross-sectional portion CS! is larger than the area of ​​the second cross-sectional portion CS2. Accordingly, in the comparative example, the volume of the first portion is larger than the volume of the second portion.

[0065]

[0046] Referring again to FIG. 4, the thick solid curve in FIG. 4 indicates the distribution amount DB of the second material in the x direction at the z coordinate position indicated by the dashed-two-dot line. The dashed-dotted line in FIG. 4 is a line indicating the position in the injector body 2B where the distribution amount DB in the x direction is maximum for each z coordinate. As described above, in the injector body 2B according to the comparative example, the volume of the first portion is larger than the volume of the second portion due to forging of the bar material 2A. As a result, the distribution of the second material in the x direction in the first axial range A1 and the second axial range A2 of the injector body 2B according to the comparative example are different from each other. More specifically, in the first axial range A! of the injector body 2B, the position where the distribution amount DB of the second substance in the x direction is maximum is shifted from the central axis, and the x coordinate of this position is a positive value rather than a circle. Specifically, the distribution amount DB of the second substance at the z coordinate position indicated by the two-dot chain line is maximum at the positive x coordinate indicated by xi, and decreases as the x coordinate moves away from xi.

[0066]

[0047] Fig. 6 is a diagram schematically showing a part of a cross section of a housing 2 according to a comparative example. The cross section of the housing 2 in Fig. 6 is a cross section along the xz plane. In Fig. 6, the cross section of the housing 2 is shown by hatching. The housing 2 shown in Fig. 6 is obtained by drilling a hole 20 along the central axis in the injector body 2B shown in Fig. 4. The two-dot chain line in Fig. 6 indicates the same position on the z coordinate as the two-dot chain line in Figs. 3 and 4.

[0067]

[0048] Among the dashed dotted lines shown in Fig. 6, those that overlap with the hatched portions indicate the positions, for each z coordinate, where the distribution quantity DB is maximum in the x direction in the housing 2. Among the dashed dotted lines shown in Fig. 6, those that do not overlap with the hatched portions indicate the positions, for each z coordinate, where the distribution quantity DB is maximum in the x direction in the injector body 2B, which is the base of the housing 2.

[0068]

[0049] Here, region R indicated by the dashed circle in Figure 6 includes the high stress portion. As shown in Figure 6, region R overlaps with the dashed line. That is, the housing 2 according to the comparative example contains a large amount of the second material in the high stress portion. As a result, the strength of the high stress portion in the comparative example is low. Therefore, the housing 2 according to the comparative example is prone to a significant decrease in strength due to the operation of the injector 1. On the other hand, the housing 2 of the injector 1 according to the embodiment reduces the amount of the second material in the high stress portion, thereby suppressing the occurrence of a significant decrease in strength. The housing 2 according to the embodiment will be described below.

[0069]

[0050] Fig. 7 is a diagram schematically illustrating a portion of the side surface of an injector body 2B according to an embodiment and the distribution of a second substance. The side view of the injector body 2B in Fig. 7 is a diagram viewed along the y direction, and the x direction in Fig. 7 corresponds to the x direction in Figs. 1 and 4, etc., and the z direction in Fig. 7 corresponds to the z direction in Figs. 1 and 4, etc. The injector body 2B in Fig. 7 is obtained by forging the bar material 2A in Fig. 3. The two-dot chain line in Fig. 7 indicates the same position as the z coordinate position indicated by the two-dot chain line in Fig. 3.

[0070] 7 , the first width of the injector body 2B in the first circumferential range a and the first axial range A1 according to the embodiment is larger than the first width in the second axial range, similar to the comparative example, due to the attachment of the inlet portion 3. However, unlike the comparative example, the first width of the injector body 2B in the second circumferential range and the first axial range A1 according to the embodiment is also larger than the first width in the second axial range.

[0071]

[0052] The shape of the injector body 2B according to the embodiment will be described in detail below with reference to Figs. 8 and 9. Fig. 8 is a diagram schematically illustrating an example of a cross section of the injector body 2B according to the embodiment taken along the xy plane. The cross section shown in Fig. 8 is the C-C cross section in Fig. 7. Fig. 9 is a diagram schematically illustrating another example of a cross section of the injector body 2B according to the embodiment taken along the xy plane. The cross section shown in Fig. 9 is the D-D cross section in Fig. 7. The cross sections shown in Figs. 8 and 9 are cross sections at different z coordinates in the first axial range A1. In Figs. 8 and 9 as well, the second rotational range is defined as all or part of the angle indicated by / 3. In this embodiment, as shown in Figures 8 and 9, the area of ​​the first cross-sectional portion CS1 is equal to the area of ​​the second cross-sectional portion CS2, and the volume of the first portion is equal to the volume of the second portion.

[0072] In the embodiment, the maximum value of the second width of the first portion is greater than the maximum value of the second width of the second portion. Here, the second width refers to the width in the x-direction. Furthermore, in the injector body 2B according to the embodiment, the maximum value of the circumferential curvature in the first circumferential range a is greater than the maximum value of the circumferential curvature in the second circumferential range in all or part of the first axial range A1.

[0073]

[0054] Referring again to FIG. 7, the thick solid curve in FIG. 7 indicates the distribution amount DB of the second substance in the x direction at the z coordinate position indicated by the dashed-two-dot line. The dashed-dotted line in FIG. 7 is a line indicating the position in the injector body 2B where the distribution amount DB in the x direction is maximum for each z coordinate. As described above, in the injector body 2B according to the embodiment, the volume of the first portion is equal to the volume of the second portion. As a result, in the injector body 2B according to the embodiment, the position where the distribution amount DB of the second substance in the x direction is maximum overlaps with the central axis not only in the second axis range but also in the first axis range A1.

[0074]

[0055] Fig. 10 is a diagram illustrating a schematic example of a portion of a cross section of a housing 2 according to an embodiment. The cross section of the housing 2 in Fig. 10 is a cross section along the xz plane. In Fig. 10, the cross section of the housing 2 is indicated by hatching. The housing 2 shown in Fig. 10 is obtained by drilling a hole 20 along the central axis in the injector body 2B shown in Fig. 7. The two-dot chain line in Fig. 10 indicates the same position as the z coordinate position indicated by the two-dot chain lines in Figs. 3 and 7.

[0075]

[0056] As shown in Fig. 10, in the housing 2 according to the embodiment, the first distance is different between the first axial range A1 and the second axial range in each of the first circumferential range a and the second circumferential range in the circumferential direction. Here, the first distance is the distance from the central axis to the end of the housing 2 in the radial direction. The portion of the housing 2 that is in the first circumferential range a and the first axial range A1 is an attachment portion for the inlet portion 3, and the first distance in this attachment portion is longer than the first distance in the second axial range. Furthermore, the first distance in the second circumferential range and the first axial range A1 is also longer than the first distance in the second axial range.

[0076]

[0057] The dashed-dotted lines in Fig. 10 indicate the positions, for each z coordinate, where the distribution amount DB in the x direction was maximum in the injector body 2B, which is the basis for the housing 2. As shown in Fig. 10, the dashed-dotted lines do not overlap with the hatched areas. That is, in the housing 2 of the embodiment, the portion containing the most second substance was removed when the hole 20 was drilled in the injector body 2B. Therefore, the housing 2 of the embodiment has a lower content of the second substance than the housing 2 of the comparative example.

[0077] Furthermore, in the embodiment, the high stress portion in the region R indicated by the dashed circle does not overlap with the dashed line. That is, the amount of the second substance contained in the high stress portion of the housing 2 according to the embodiment is less than that of the comparative example. Therefore, the high stress portion in the embodiment has higher strength than that of the comparative example. Therefore, the housing 2 according to the embodiment is less likely to experience a significant decrease in strength due to the operation of the injector 1 than that of the comparative example.

[0078]

[0059] In the embodiment, the area of ​​the first cross-sectional portion CS1 and the area of ​​the second cross-sectional portion CS2 in the injector body 2B are equal, and the volume of the first portion and the volume of the second portion are equal. However, the present invention is not limited to this. For example, the volume of the second portion may be larger than the volume of the first portion. Alternatively, the volume of the second portion may be equal to or greater than a specified ratio, such as 90% or more of the volume of the first portion. The specified ratio may be determined from at least one of the first width and second width of the first portion and the diameter of the hole 2O drilled in the injector body 2B when manufacturing the housing 2.

[0060] The following describes the effects of the manufacturing method for the housing 2 of the injector 1 according to the embodiment. The manufacturing method for the housing 2 of the injector 1 according to this embodiment includes a first step, a second step, and a third step. The first step is to obtain a bar material 2A by melting and extruding a base material. The base material is a material in which a second material is added to a first material, which is the main component of the housing 2. The second material has a melting point lower than that of the first material. The second step is to forge the bar material 2A to obtain an injector body 2B. The third step is to obtain the housing 2 by drilling a hole 20 in the injector body 2B along the axial direction, which is the direction of the central axis of the injector body 2B. In the injector body 2B according to this embodiment, a first width, which is a width in the radial direction from the central axis, differs between a predetermined first axial range A1 in the axial direction and a second axial range other than the first axial range A1 in each of a first circumferential range a and a second axial range in the circumferential direction. In the injector body 2B, an inlet portion 3, which introduces the injection target into the housing 2, is attached at a position within the first circumferential range a and the first axial range A1, so that the first width within the first circumferential range a and the first axial range A1 is larger than the first width within the second axial range.Here, if the central axis is the z-axis in the xyz space and the radial direction from the central axis toward the center of the first circumferential range a is the x-direction, the second circumferential range is located on either side of the y-axis with the first circumferential range a. The first width in the second circumferential range and first axis range A1 is larger than the first width in the second axis range.

[0079]

[0061] According to the manufacturing method of the housing 2 of the injector 1 according to the embodiment, in the injector body 2B, not only the first width in the first circumferential range a and the first axial range A1 but also the first width in the second circumferential range and the first axial range A1 are larger than the first width in the second axial range. This makes it possible to prevent much of the low-strength second material from distributing toward the first circumferential range a, i.e., toward the positive side of the x-direction, in the first axial range A1 of the injector body 2B according to the embodiment. This makes it possible to prevent a decrease in strength of the high-stress portion located in the first circumferential range a and the first axial range A1 in the housing 2 obtained from the injector body 2B. This prevents a significant decrease in strength of the high-stress portion during operation of the injector 1, resulting in improved durability of the injector 1 compared to conventional injectors.

[0080]

[0062] In the injector body 2B according to the embodiment, of two portions on either side of the yz plane in all or part of the first axial range A1, the volume of the first portion including the first circumferential range a is equal to or less than the volume of the second portion including the second circumferential range. This further reduces the content of the second substance in the first circumferential range a and the first axial range A1 in the injector body 2B, and as a result, further reduces the content of the second substance in the high-stress portion of the housing 2 located in the first circumferential range a and the first axial range A1. This further prevents a significant decrease in strength in the high-stress portion, further improving the durability of the injector 1.

[0081]

[0063] In the embodiment, the volume of the first portion and the volume of the second portion are equal to each other. As a result, the distribution amount DB of the second substance in the injector body 2B is maximum at the central axis and decreases with increasing distance from the central axis. Therefore, when forming the housing 2 by drilling the hole 20 in the injector body 2B along the central axis, much of the second substance is removed, and the amount of the second substance in the housing 2 is reduced. This improves the durability of the housing 2.

[0082]

[0064] In the embodiment, the maximum value of the second width of the first portion is greater than the maximum value of the second width of the second portion. This facilitates processing of the second portion of the injector body 2B.

[0083] In the injector body 2B according to the embodiment, the maximum value of the circumferential curvature in the first circumferential range A1 is greater than the maximum value of the circumferential curvature in the second circumferential range A1 in all or part of the first axial range A1. This makes it easier to process the injector body 2B.

[0084]

[0066] The injector 1 according to this embodiment includes a housing 2 that forms an outer shell, and an inlet portion 3 that allows the injection target to flow into the housing 2. The housing 2 is obtained by melting and forging a base material in which a second material is added to a first material. The second material has a lower melting point than the melting point of the first material. The housing 2 has a first axial range A1 and a second axial range A1 in the circumferential direction, respectively. The inlet portion 3 is attached at a position in the first axial range A1, and the first distance in the first axial range A1 is longer than the first distance in the second axial range A1. Furthermore, the first distance in the second rotation range and first axis range A1 is longer than the first distance in the second axis range.

[0085]

[0067] In the injector 1 according to this embodiment, in the housing 2, not only the first distance in the first circumferential range a and the first axial range A1 but also the first distance in the second circumferential range and the first axial range A1 is longer than the first distance in the second axial range. In the process of manufacturing such a housing 2, the amount of the second substance contained in the high stress portion in the first circumferential range a and the first axial range A1 can be reduced compared to conventional methods. This improves the strength of the high stress portion compared to conventional methods. This prevents a significant decrease in strength of the high stress portion during operation of the injector 1, resulting in improved durability of the injector 1.

[0086] [Explanation of symbols]

[0087] [ 0 0 6 8 ]

[0088] ! Injector, 2 Housing, 2A Bar material, 2B Injector body, 3 Inlet portion, 4 Nozzle body, 5 Nozzle needle, 6 Nozzle spring, 7 Nozzle nut, 8 Valve, 9 Pressure control portion, 20 Hole, 21 Second flow path, 22 Spring chamber, 23 Third flow path, 24 Pressure introduction chamber, 3〇 First flow path, 4〇 Fuel injection hole, 41 Seat portion, 42 Fuel sump chamber, 50 Pressure receiving portion, 8〇 Valve body, 8I Valve piston, 82 Piston chamber, 83 First end, 84 Control pressure chamber, 85 Inlet side orifice passage, 86 Opening and closing orifice passage, 9〇 Electromagnet, 91 Armature plate, 92 Armature bolt, 92a shaft section, 92b head section, 93 armature guide, 94 spring, 95 holder, 95a fuel return path, 96 electromagnet housing, 97 housing nut, 98 control valve body, A! first shaft area, CS1 first cross-sectional area, CS2 second cross-sectional area, R area, « first circumference area.

Claims

[Document name] Scope of claims

1. A method for manufacturing a housing (2) of an injector (1), comprising the steps of: obtaining a bar material (2A) by melting and extruding a base material in which a second material having a melting point lower than that of a first material that is a main component of the housing (1); forging the bar material (2A) to obtain an injector body (2B); and obtaining the housing (2) by drilling a hole (20) in the injector body (2B) along an axial direction that is a direction of a central axis of the injector body (2B) obtained from the bar material (2A), wherein the injector body (2B) has a first width that is a width in a radial direction from the central axis in a first circumferential range (a) and a second circumferential range (b) in the axial direction, the first width being a width in a radial direction from the central axis, the first width being a width in a predetermined first axial range (A1) and a second axial range (A2) in the axial direction. a second axial range other than the first circumferential range (a) (A1) and a second axial range other than the first circumferential range (a) (A1), and an inlet portion (3) for introducing an injection target into the housing (2) is attached at a position in the first circumferential range (a) and the first axial range (A1), so that the first width in the first circumferential range (a) and the first axial range (A1) is larger than the first width in the second axial range, and when the central axis is defined as the z-axis in an xyz space and when a radial direction from the central axis toward the center of the first circumferential range (a) is defined as the x-direction, the second circumferential range is located on either side of the first circumferential range (a) and the y-axis, and the first width in the second circumferential range and the first axial range (A1) is larger than the first width in the second axial range.

2. A method for manufacturing a housing (2) of an injector (1) according to claim 1, wherein, of two portions of the injector body (2B) that sandwich a yz plane in all or part of the first axial range (A1), the volume of the first portion that is the portion that includes the first circumferential range (a) is equal to or less than the volume of the second portion that is the portion that includes the second circumferential range.

3. The injector according to claim 2, wherein the volume of the first portion and the volume of the second portion are equal to each other. (1) A manufacturing method of the housing (2).

4. A method for manufacturing a housing (2) of an injector (1) as set forth in claim 1, wherein, of two portions of the injector body (2B) on either side of a yz plane in all or part of the first axial range (A1), a portion including the first circumferential range (a) is defined as a first portion, and a portion including the second circumferential range is defined as a second portion, and when a width of the injector body (2B) in the x direction is defined as a second width, a maximum value of the second width of the first portion is greater than a maximum value of the second width of the second portion.

5. The method for manufacturing a housing (2) of an injector (1) according to claim 1, wherein the injector body (2B) has a maximum value of the curvature in the circumferential direction in the first circumferential range (a) greater than a maximum value of the curvature in the circumferential direction in the second circumferential range over all or part of the first axial range (A1).

6. An injector (1) comprising a housing (2) forming an outer shell, and an inlet portion (3) for introducing an injection target into the housing (2), wherein the housing (2) is obtained by melting and forging a base material in which a second material having a melting point lower than that of a first material is added to a first material, and the base material is formed by forging the melted material, and a first distance, which is a distance from a central axis of the housing (2) to an end of the housing (2) in a radial direction, in each of a first circumferential range (a) and a second circumferential range in a circumferential direction of the housing (2), differs between a predetermined first axial range (A1) in an axial direction that is the direction of the central axis and a second axial range other than the first axial range (A1), and the inlet portion (3) is attached at a position in the first circumferential range (a) and the first axial range (A1), The injector (1) has a first distance in the first circumferential range (a) and the first axis range (A1) that is longer than the first distance in the second axis range, and when the central axis is defined as the z-axis in an xyz space and when the radial direction from the central axis toward the center of the first circumferential range (a) is defined as the x-direction, the second circumferential range is located on either side of the first circumferential range (a) with respect to the y-axis, and the first distance in the second circumferential range and the first axis range (A1) that is longer than the distance in the second axis range.

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