JP3003764B2 - Nozzle manufacturing method, nozzle and fuel injection valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nozzle for ejecting a fluid, and more particularly to a method of manufacturing a nozzle having an orifice for measuring a flow rate, a nozzle, and a fuel injection valve using the nozzle.

[0002]

2. Description of the Related Art Conventionally, as a method of processing a valve body sheet surface or an orifice provided in a nozzle serving as a fuel injection hole of a fuel injection valve, there has been a method of grinding and polishing. Has required low productivity and high cost due to the necessity of a plurality of processing procedures, complicated grinding wheel wear control, and the like. Therefore, in order to solve these difficulties, a known technique by plastic working has been proposed, for example, as disclosed in Japanese Patent Application Laid-Open No. 4-191575.

[0003]

However, the above known technique has the following problems. That is, when transfer molding the sheet portion to the nozzle material, a punch having substantially the same shape as the sheet portion is used for the work surface located near the center of the nozzle material having a substantially H-shaped vertical section. Since the extrusion process is performed on the lower surface side of the nozzle bottom, the material of the nozzle material that has been plastically deformed and extruded protrudes downward in a convex shape. Therefore, in order to form an orifice having a predetermined length in the channel direction by punching out the orifice after this sheet portion forming procedure, a step of removing the protruding portion is required separately, and it becomes difficult to improve productivity. There was an inconvenience.

[0004] In addition, a concave surface substantially similar to the shape of the sheet portion is formed on the upper surface of a die installed on the back side of the surface to be processed at the time of the extrusion, and the material of the nozzle material to be extruded is directed toward the concave surface. The degree of work hardening is small because it is plastically deformed in such a manner that it spreads in the same shape as the sheet part. Therefore, when the orifice is punched after the sheet portion forming procedure, a small dripping occurs at the orifice entrance, which affects the flow coefficient of the orifice and makes the supply flow rate unstable, so that high-precision fuel injection control is difficult. There was an inconvenience of becoming.

Furthermore, since the heat treatment (quenching) is performed only once after the transfer molding and the orifice punching of the sheet portion, the distortion of the residual stress of the plastic working by the transfer molding and the distortion of the heat treatment deformation are synergistic during the quenching. When this occurs, large deformation occurs, and the accuracy of roundness, surface roughness, etc., is greatly reduced. Therefore, it is difficult to perform a sufficient correction even if the correction is performed by local forming with a punch after quenching, and as a result, the oil tightness of the seat portion is reduced, so that highly accurate fuel injection control becomes difficult. That is, there is a disadvantage that the mixture at the time of starting the engine becomes rich and the startability of the engine deteriorates.

A first object of the present invention is to provide a nozzle manufacturing method, a nozzle, and a fuel injection valve, which can shorten the nozzle processing step and improve productivity.

A second object of the present invention is to provide a method of manufacturing a nozzle, a nozzle, and a fuel injection valve which enable high-accuracy flow control by stabilizing a supply flow rate.

A third object of the present invention is to provide a method of manufacturing a nozzle, a nozzle, and a fuel injection valve which enable highly accurate flow rate control by improving the oil tightness of a seat portion.

[0009]

According to a first aspect of the present invention, there is provided a method of manufacturing a nozzle having an orifice for measuring a fluid, the method comprising: A first step of performing a pressure forming process on a cylindrical nozzle material with a forming punch, and forming a substantially conical concave surface provided on the inlet side of the orifice at the bottom of the nozzle material; and a punching punch from the concave surface side. And a second step of forming the orifice at the bottom of the nozzle material, and the first step is to press the material flowing toward the lower surface of the nozzle by pressure molding, A forming punch and a forming die arranged on the outlet side of the orifice are used to extrude the outer peripheral side of the orifice, and the orifice processing portion where the orifice is formed by the punching process in the second procedure is described. Only, method of manufacturing a nozzle which is a procedure for adjusting a predetermined size is provided.

Preferably, in the method for manufacturing a nozzle, a method for manufacturing a nozzle is provided, wherein a martensitic stainless steel having a carbon content of 0.25% or more is used as the nozzle material.

Preferably, in the method for manufacturing a nozzle, the first procedure is a procedure for work hardening the hardness of the orifice processing portion to Hv270 or more. .

[0012]

[0013]

[0014]

[0015]

According to a second aspect of the present invention, there is provided a method of manufacturing a nozzle having an orifice for measuring a fluid. Press forming with a forming punch,
A first step of forming a substantially conical concave surface provided on the inlet side of the orifice on the bottom of the nozzle material, and punching with a punch from the concave surface to form the orifice on the bottom of the nozzle material. A second procedure to perform an annealing process on the nozzle material on which the orifice is formed, and a local forming punch on a seat portion with a valve body of the concave surface that is minutely deformed by recrystallization of stress strain due to plastic deformation due to the annealing. And a third step of quenching the nozzle material having been subjected to the local press forming after the local press forming in the first step. The material flowing to the lower surface side of the nozzle is extruded to the outer peripheral side of the orifice with the forming punch and a forming die arranged on the outlet side of the orifice,
A method for manufacturing a nozzle is provided, wherein the thickness of the orifice processing portion where the orifice is formed by the punching process in the second procedure is adjusted to a predetermined dimension.

According to a third aspect of the present invention, there is provided a nozzle having an orifice for measuring a fluid, the nozzle being provided on an inlet side of the orifice. A substantially conical concave surface formed by pressure forming from the inlet side of the orifice, and provided at the outlet side of the orifice, formed by being extruded from the inlet side of the orifice to the outer peripheral side of the orifice. And an orifice,
A sharp edge formed by punching from the inlet side of the orifice and a shearing cylindrical surface following the edge are formed to have a predetermined length in the flow direction by the extrusion. Is provided.

[0018]

[0019]

According to a fourth aspect of the present invention, there is provided a nozzle having an orifice for measuring a fluid, wherein the orifice has a sheet portion at an inlet side of the orifice . It has a substantially conical concave surface,
The concave surface is formed by pressure molding from the inlet side of the orifice, and after being subjected to annealing, local pressure molding is performed from the inlet side of the orifice to correct the sheet shape, and further quenching is performed. and decorated with, the said orifice, before the concave is subjected to annealing, has an edge portion which is formed by being stamped from the inlet side of the orifice and shear cylindrical surface following the edge portion A nozzle is provided.

[0021]

According to a fifth aspect of the present invention, there is provided a nozzle having an orifice for measuring a fluid, the nozzle being provided on an inlet side of the orifice. It is formed by pressure forming from the inlet side of the orifice, and after being annealed, is subjected to local pressure forming from the inlet side of the orifice to correct the sheet portion shape, and is further subjected to quenching. A conical concave surface, and an extruded portion provided on the outlet side of the orifice and formed by being extruded from the inlet side of the orifice to the outer peripheral side of the orifice, wherein the orifice has the concave surface formed by annealing. Before being subjected to a sharp edge formed by punching from the inlet side of the orifice and a shear cylinder following this edge Comprising a nozzle, characterized in that it is formed in a predetermined flow direction length by the extrusion, it is provided.

According to a sixth aspect of the present invention, there is provided a valve element operated by an electromagnet, a valve seat accommodating the valve element and constituting a valve. A nozzle provided with an orifice provided on the downstream side of the valve seat, and a fuel injection valve that opens and closes the valve by the action of the electromagnet to inject fuel from the orifice; A substantially conical concave surface formed by pressure forming from the inlet side of the orifice, provided on the inlet side, and an outer peripheral side of the orifice from the inlet side of the orifice is provided on the outlet side of the orifice. And an orifice formed by being extruded from the inlet side of the orifice. Comprising a Jo edge portion and shear the cylindrical surface following the edge portion, the fuel injection valve, characterized in that it is formed in a predetermined flow direction length by the extrusion, it is provided.

According to a seventh aspect of the present invention, there is provided a valve element operated by an electromagnet, a valve seat accommodating the valve element and constituting a valve. A nozzle provided with an orifice provided on the downstream side of the valve seat, and a fuel injection valve that opens and closes the valve by the action of the electromagnet to inject fuel from the orifice; to the inlet side
It has a substantially conical concave surface as a seat, and this concave surface is
Serial formed by being machined pressing from the inlet side of the orifice, from the inlet side of the orifice after being subjected to annealing is processed locally pressing is corrected seat shape, further tempering is performed The orifice has an edge portion formed by punching from the inlet side of the orifice before the concave surface is annealed, and a shear cylindrical surface following the edge portion. Is provided.

According to an eighth aspect of the present invention, to achieve the first to third objects, a valve element operated by an electromagnet, a valve seat accommodating the valve element and constituting a valve are provided. A nozzle provided with an orifice provided on the downstream side of the valve seat, and a fuel injection valve that opens and closes the valve by the action of the electromagnet to inject fuel from the orifice; It is provided on the inlet side, formed by being subjected to pressure forming from the inlet side of the orifice, and after being subjected to annealing, is subjected to local press forming from the inlet side of the orifice to correct the sheet portion shape, and A quenched substantially conical concave surface is provided on the outlet side of the orifice, and is formed by being extruded from the inlet side of the orifice to the outer peripheral side of the orifice. The orifice has a sharp edge formed by being punched from the inlet side of the orifice before the concave surface is annealed, and the orifice follows the edge. A fuel injection valve having a shear cylindrical surface and being formed to have a predetermined length in a flow direction by the extrusion process is provided.

[0026]

According to the first concept of the present invention constructed as described above, in the first procedure, a pressure forming process is performed on a bottomed cylindrical nozzle material with a forming punch, and the pressure is provided on the inlet side of the orifice. A substantially conical concave surface is formed at the bottom of the nozzle material. At this time, the material flowing to the lower surface side of the nozzle by the pressure forming process is extruded to the outer peripheral side of the orifice by a forming punch and a forming die arranged at the outlet side of the orifice, and the orifice is formed in a second procedure later. The thickness of the orifice processed portion is adjusted to a predetermined size. With this, the thickness of the orifice processing part can be formed at the same time when forming the concave surface,
Since the material flowing to the lower surface of the nozzle does not project in a convex shape as in the related art, this projecting portion removing step is not required. In addition, since the degree of work hardening of the orifice processing portion can be increased and the work hardening index (n value) of the material decreases, in the second procedure, the orifice is punched from the concave side with a punch and the orifice is formed at the bottom of the nozzle material. When forming into
It is possible to prevent the occurrence of minute dripping at the orifice entrance portion following the concave surface, and to sharply sharpen the shape of the edge portion. Further, the processing can be easily performed with good reproducibility.

Further, as a nozzle material, a carbon content of 0.5 is used.
By using 25% or more of martensitic stainless steel, sufficient hardness after quenching can be reliably obtained. Further, in the first procedure, the hardness of the orifice processed portion is hardened to Hv270 or more, whereby the occurrence of minute dripping at the time of orifice punching can be reliably prevented .

Further, in a second concept of the present invention,
After forming a substantially conical concave surface on the bottom of the nozzle material in the first procedure, punching is performed in the second procedure to form an orifice on the bottom of the nozzle material. Then, in a third procedure, first, a residual stress generated at the time of punching in the second procedure is once dissipated by annealing the nozzle material having the orifice formed therein. Next, local deformation of the concave shape is performed by performing local pressure forming with a local forming punch on the sheet portion with the valve body, out of the concave surface that is minutely deformed by recrystallization of stress strain due to plastic deformation due to annealing. Do. And
By quenching the nozzle material that has been subjected to the local pressure forming process, a slight residual stress due to the local stress is dissipated. At this time, since the material is softened by annealing before the local forming, the springback at the time of the local forming can be reduced, and accurate forming can be performed with a low load. Also, at this time, by performing annealing and local forming, the residual stress at the time of quenching is limited to a local one, and the magnitude of the residual stress is extremely small, so that only quenching without annealing is performed. As in the conventional case, since a large amount of residual stress is released during quenching, the accuracy of roundness, surface roughness, and the like does not significantly decrease.

[0029]

[0030]

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. A first embodiment of the present invention will be described with reference to FIGS. This embodiment is an embodiment of a nozzle manufacturing method and a nozzle manufactured by the manufacturing method. FIGS. 2 and 3 show the structure of the nozzle 1 manufactured by the manufacturing method of this embodiment. FIG. 2 is a cross-sectional view of the nozzle 1, and FIG.
It is an enlarged view of a part. 2 and 3, the nozzle 1
Is, for example, an electromagnetic fuel injection valve 10 shown in FIG.
An orifice 9 for measuring a fluid, a substantially conical sheet portion 1 a provided on the inlet side of the orifice 9, and an orifice 9 provided on the outlet side of the orifice 9. The orifice 9 has a concentric substantially annular ring portion 1b, and the orifice 9 has a sharp edge portion 9b and a shearing cylindrical surface 9a following the edge portion 9b.

Hereinafter, the procedure of the method for manufacturing the nozzle 1 having the above structure will be described in detail. First, a nozzle material 11 to be a material for manufacturing the nozzle 1 is prepared. FIG. 4 shows the structure of the nozzle blank 11. In FIG. 4, the nozzle material 11 is made of martensitic stainless steel, and has a carbon content of 0.1 so that a sufficient hardness can be reliably obtained after a quenching step performed later.
25% or more. In addition, the shape of the nozzle material 11 is a cylindrical shape (cylindrical shape) having a bottom portion 2a to be a processed portion (sheet portion forming portion). The bottom 2a is disposed in the middle of the nozzle material 11 in the axial direction in a raised bottom state. With the bottom 2a as a boundary, a cylindrical inner wall is formed by an upper inner wall 2b-1 and a lower inner wall 2b-2. And divided into

Next, the sheet portion 1a is
Is molded. This procedure will be described with reference to FIG. 1 and FIG. 1 and 5, a forming apparatus 100 for forming a sheet portion 1a on a nozzle material 11 is shown.
Is a punch 3 made of cemented carbide having a roundness of 1 μm or less, a die 4a, a die 4b installed on the inner periphery of the die 4a, and a die 4a and the nozzle material 11 installed on the inner periphery. A guide 5, an upper slide 6 which is a hydraulic pressurizing mechanism, a knockout pin 7, and a stripper 8 fixed to the knockout pin 7.

The punch 3 has a transfer sheet die 3a having a shape similar to the sheet portion 1a formed at the end thereof, and a stopper 3c which is a flat surface formed around the sheet die 3a. The tip of the die 4b has a flat surface 4c that is sufficient for processing the orifice 9 in a later step, and a tapered surface 4e that is processed into a convex substantially conical shape. A substantially annular groove 4d (discussed below) is formed by the inner wall of 4a to allow the plastic flow of the nozzle material to escape.

In the molding apparatus 100 having the above-described configuration, first, the nozzle material 11 is inserted so that the punch 3 can penetrate the upper inner wall 2b-1 and the dies 4a and 4b are inserted into the lower inner wall 2b-2. Is set by being guided by the guide 5 so as to enter. Then, the punch 3 fixed to the upper slide 6 descends together with the upper slide 6, the tip 3 a of the punch 3 enters along the upper inner wall 2 b-1 of the nozzle material 11, and the punch 3 further descends to move the nozzle material 11. The center of the upper surface of the bottom 2a is pressed with a predetermined load necessary for plastic working. Due to this pressure, plastic flow starts at the center of the upper surface of the bottom portion 2a, which is the portion to be processed, and the sheet portion 1a is formed.
At the same time, the material of the lower surface portion of the bottom portion 2a immediately below the sheet portion 1a is placed in the annular groove 4d formed by the inner wall of the die 4a and the tapered surface 4e of the die 4b (that is, on the outer peripheral side of the orifice 9 formed later). ) Flow and extrude (see FIG. 5). At this time, the height of the flat surface 4c, which is the tip of the die 4b, is adjusted in advance so as to be the same height as the lower surface 1d of the nozzle bottom, whereby the orifice processing portion 1e where the orifice 9 is punched later is formed. Is adjusted to a predetermined size t, and as a result, the length of the orifice 9 in the flow path direction can be set to a predetermined size (= t). Then, the stopper 3c of the punch 3 is moved to the bottom 2a.
When the punch 3 is press-formed until it hits the upper surface, the sheet portion 1a is transfer-molded to the bottom portion 2a, and a substantially annular ring portion concentric with an orifice 9 formed later by a material extruded by plastic flow. 1b is molded.

When the above-mentioned molding is completed, the upper slide 6 is raised, and the punch 3 is separated from the nozzle blank 11 via the knockout pin 7 and the stripper 8.

When the press forming of the sheet portion 1a is completed, the orifice 9 is punched. This procedure will be described with reference to FIG. In FIG. 6, a punching device 20 for punching the orifice 9 is provided.
Reference numeral 0 denotes a punch 24 having a tip cutting edge 24a finished to a predetermined size, and a punch guide 2 for guiding the punch 24.
5, a die guide 27 set on a die set (not shown), and a die 26 set on an inner peripheral portion of the die guide 27.
And

In the punching apparatus 200 having the above-described configuration, first, the sheet portion 1a and the ring
The nozzle blank 11 on which b is formed is set on the die 26 such that the sheet portion 1a faces upward. Then, the upper die (not shown) is lowered by a mechanical press machine or the like, and first, the punch guide 25 is moved to the upper inner wall 2b-
1, the center of the nozzle material 11 is performed, and then the upper die is further lowered, and the tip cutting edge portion 24a of the punch 24 punches the orifice processing portion 1e of the nozzle material 11 from the sheet portion 1a side, and the orifice 9 is removed. Form. At this time, the punched waste 23 is dropped into the cutting blade 26a of the die 26. The difference between the outer diameter of the cutting edge portion 24a of the tip 24 of the punch 24 and the inner diameter of the cutting edge portion 26a of the die 26, that is, the punching clearance is preferably 10 to 15%.

The above-described molding of the sheet portion 1a and the orifice 9
In the punching procedure, the orifice processing portion 1e is formed so that the thickness of the orifice processing portion 1e becomes t at the same time as the sheet portion 1a is formed, and the material flowing to the nozzle lower surface side does not protrude in the orifice processing portion 1e in the conventional manner. . That is, it is not necessary to delete the center of the ring portion 1b before the orifice 9 is punched. At this time, since the orifice processed portion 1e is formed to have a thickness of about 1/4, the degree of work hardening is large, and the work hardening index (n
Value) becomes smaller. For example, the hardness before molding is about Hv200.
Material hardens to about Hv270 or more after molding. Therefore,
When the orifice processing portion 1e is punched out from the sheet portion 1a side by the punch 24 to form the orifice 9, no small dripping occurs at the inlet portion following the orifice 9 and a highly accurate shear cylindrical surface 9a is formed (see FIG. 3). ). Therefore, the shape of the edge portion 9b, which is the inlet of the orifice 9, which particularly affects the flow coefficient, can be machined into an extremely stable and sharp shape free from burrs and the like. At this time, the reproducibility is good and the processing can be easily performed.

After the orifice 9 has been punched, the nozzle blank 11 is annealed and the sheet 1a after the annealing is locally formed. After forming the orifice 9 in the nozzle material 11, first, the nozzle material 11 is annealed to remove the residual stress generated in the above-described sheet part 1a forming procedure. By this annealing treatment, the residual stress at the time of forming the sheet portion 1a is released, and the accuracy of the sheet portion 1a, such as surface roughness and roundness, is reduced. It is possible to improve.

After the above-described annealing, local forming of the sheet portion 1a is performed. This procedure will be described with reference to FIG. In FIG. 7, a local forming apparatus 300 for locally forming the sheet portion 1 a includes a male top 19 provided with a ball 21 as a forming portion at a tip thereof, and a male top 19 opposite to the male top 19 across the nozzle material 11. A female top 18 provided with a support portion 18a for supporting the lower inner wall 2b-2 of the nozzle material 11, and a male top 1
And a guide body 20 that guides the guide body 9. Ball 21
Has substantially the same shape as, for example, a valve body 15 of the fuel injection valve 10 shown in FIG. 8 described later, that is, a substantially spherical shape. In addition, from the viewpoint of increasing the molding accuracy, the ball 21 is
For example, it is desirable that the material be a cemented carbide having a roundness of 0.5 μm or less.

In the local molding apparatus 300 having the above-described configuration, first, the support portion 18a of the female frame 18 and the male frame 19 are set in the guide body 20 with the nozzle material 11 interposed therebetween. . Then, the male top 19 is lowered by a hydraulic press machine or the like to press the seat portion 1a, and the seat portion 1a is locally plastically deformed along the shape of the ball 21. That is, the shape of the sheet portion 1a slightly deformed by the above-described annealing is corrected.

After the annealing of the nozzle material 11 and the local forming of the sheet portion 1a as described above, the nozzle material 11
Is subjected to quenching to remove residual stress generated by local forming. In the above-described steps of annealing, local forming, and quenching, the nozzle material 11 is annealed before the local forming to soften the material. Roundness, surface roughness, etc. can be accurately transferred with a low load.
Further, at this time, through the annealing and the local forming, the residual stress immediately before the quenching is limited to a local stress at the time of the local forming by the ball 21 (for example, in the vicinity of the seat position of the valve body of the fuel injection valve). The magnitude of the residual stress is extremely small. Therefore, unlike the conventional case in which only quenching is performed without annealing, a large amount of residual stress is not released at the time of quenching, and it is possible to prevent the accuracy such as roundness and surface roughness from being significantly reduced.

The quenching process causes another slight deformation of the sheet portion 1a and slightly lowers the accuracy of roundness, surface roughness, etc., so that extremely high accuracy (ie, extremely high oil tightness in the fuel injection valve) is obtained. However, after the quenching, the local forming process using the ball 21 described above with reference to FIG. 7 is performed again. As a result, it is possible to recover the accuracy, such as the roundness and the surface roughness, slightly lowered by the quenching. Through the processing procedure described above, the nozzle material 11 shown in FIG.
Thus, the above-described nozzle 1 shown in FIG. 2 is completed.

As described above, according to the nozzle manufacturing method of the present embodiment, the thickness t of the orifice processing portion 1e can be simultaneously formed at the time of forming the sheet portion 1a, so that the step of removing the protruding portion as in the prior art is unnecessary. Become. Therefore, the processing process of the nozzle can be shortened, the entire manufacturing process can be rationalized, the manufacturing equipment can be simplified, and the productivity can be improved, so that the manufacturing cost can be reduced. In addition, the degree of work hardening of the orifice processing portion 1e can be increased, and the work hardening index (n value) of the material decreases, so that a small dripping occurs at the entrance of the orifice 9 following the sheet portion 1a during punching. And the shape of the edge portion 9b can be sharpened extremely stably. Further, the processing can be easily performed with good reproducibility. Therefore, the influence on the flow coefficient of the orifice 9 is reduced and the flow rate supplied by the orifice 9 is stabilized, so that the flow rate can be controlled with high accuracy. Furthermore, since the nozzle material 11 is annealed before the local forming by the ball 21 to soften the material, the springback at the time of the local forming is reduced, and the forming can be performed with low load and high accuracy. Also, at this time, since the magnitude of the residual stress immediately before the final quenching is extremely small by annealing and local forming, a large residual stress is released at the time of quenching, and the roundness, surface roughness, etc. There is no significant decrease in accuracy. Therefore, the accuracy of the roundness, the surface roughness, and the like can be improved as compared with the related art, so that the flow rate can be controlled with high accuracy.

In the above embodiment, martensitic stainless steel is used as the material of the nozzle material 11, but the material is not limited to this, and a material suitable for other uses may be used.

A second embodiment of the present invention will be described with reference to FIGS. This embodiment is an embodiment of a fuel injection valve provided with the nozzle 1 described in the first embodiment. The same reference numerals are given to members equivalent to those in the first embodiment. FIG. 8 shows a sectional structure of the electromagnetic fuel injection valve 10 according to the present embodiment. 8, the electromagnetic fuel injection valve 10 of the present embodiment has a valve body 15 at the tip and a movable valve 14 which is operated by an electromagnetic coil 31.
, A spring 17 for applying a biasing force to the movable valve 14, a stopper 28 at the stroke end of the movable valve 14, a swirler 16 for imparting a turning force to the fuel to promote atomization, and a magnetic circuit together with the electromagnetic coil 31. It has a yoke 12, a core 13, and the nozzle 1.

The nozzle 1 is manufactured by the manufacturing method of the first embodiment described above, and includes a sheet surface 1a and an orifice 9 provided downstream of the sheet surface 1a. The seat surface 1 a accommodates the valve body 15 to form a valve, and has a structure in which the valve is opened and closed by the action of the electromagnetic coil 31 to inject fuel from the orifice 9.

The fuel injection valve 1 of the present embodiment having the above configuration
The operation of 0 will be described below. Since the fuel injection valve 10 includes the nozzle 1 manufactured by the manufacturing method of the first embodiment, (1) as described in the first embodiment
Shortening of machining process, (2) stabilization of orifice supply flow rate,
(3) The three effects of improving the oil tightness of the seat portion can be obtained. Of these (2) and (3), FIGS.
This will be described in detail with reference to FIG.

(2) Stabilization of Orifice Supply Flow In order to confirm the effect of orifice supply flow stabilization of the electromagnetic fuel injection valve 10 according to the present embodiment, the inventors of the present application measured variations in fuel injection amount. . The result is shown in FIG. 9 (a) and 9 (b), the abscissa represents the actually injected fuel injection value when the fuel injection amount is set to a predetermined flow rate indicated by oblique lines, and the ordinate represents the frequency of injection of each fuel injection amount. And the variation of the fuel injection amount. FIG.
FIG. 9A shows a measurement result of the nozzle 1 of the fuel injection valve 10 of the present embodiment manufactured by the procedure of the manufacturing method of the first embodiment, and FIG. 9B shows a comparative example of the present embodiment. As
It is a measurement result of the fuel injection valve provided with the nozzle which performed annealing of the nozzle raw material 11 after the sheet | seat part 1a shaping | molding and before the orifice 9 punching process. FIGS. 10 and 11 show the structure of the nozzle 101 provided in the fuel injection valve of this comparative example.
FIG. 10 is a sectional view of a main part of the nozzle 101 and substantially corresponds to FIG. 2 of the first embodiment, and FIG.
It is an enlarged view of a middle P part. 10 and 11, as described above, the nozzle 101 performs annealing of the nozzle material 11 after forming the sheet portion 1a, and further thereafter,
The orifice 9 is formed by punching the orifice processing portion 1e. That is, since the orifice processing portion 1e is stamped in a state where it has not been subjected to work hardening, a minute dripping portion having a length ι ₁ , ι ₂ (see FIG. 11) is generated at the inlet of the orifice 9. ing. And the flow coefficient of the orifice 9 varies due to the variation of the length ι ₁ , ι _{2 of the} dripping portion,
As shown in FIG. 9B, the fuel injection amount widely varies before and after the predetermined set flow rate.

On the other hand, in the nozzle 1 provided in the fuel injection valve 10 of this embodiment, as described with reference to FIG. 3 in the first embodiment, the degree of work hardening of the orifice processing portion 1e is large. Orifice processing part 1
When the orifice 9 is formed by punching e, a small-sized dripping does not occur at the inlet portion following the orifice 9 and a highly accurate shear cylindrical surface 9a is formed (see FIG. 3). As a result, FIG.
As shown in (a), the variation in the fuel injection amount before and after the predetermined set flow rate can be reduced to about 程度 of the comparative example.

(3) Improving the Oil Tightness of the Seat In order to confirm the effect of improving the oil tightness of the seat of the electromagnetic fuel injection valve 10 according to this embodiment, the inventors of the present invention sought to improve the fuel leakage from the fuel injection valve. Was measured. The result is shown in FIG. FIG. 12 shows the result of measuring the fuel leak at that time by closing the nozzle each time each manufacturing process is completed. The horizontal axis represents each manufacturing process, and the vertical axis represents the fuel leak amount. Things. 12, the solid line indicates the measurement result of the fuel injection valve 10 of the present embodiment including the nozzle 1 manufactured according to the procedure of the manufacturing method of the first embodiment, and the broken line indicates
As a comparative example, it is a measurement result of a fuel injection valve provided with a nozzle manufactured without performing only the annealing procedure in the manufacturing method of the first embodiment.

When comparing the measurement results of the present embodiment with the measurement results of the comparative example, first, in the fuel injection valve according to the comparative example,
The first local forming after forming the sheet portion and punching out the orifice slightly reduces fuel leakage (FIG. 12B).
However, since annealing is not performed before quenching, a large amount of residual stress is released at the time of quenching and accuracy such as roundness and surface roughness is greatly reduced. The tendency is shown (FIG. 12 (C)). As a result, even if the accuracy is restored in the second local forming after quenching, the value of the leakage amount remains relatively large, and is only about the same as the amount of fuel leakage immediately after forming the sheet portion and punching out the orifice. It can be seen that improvement has not been achieved (FIG. 12D).

On the other hand, the fuel injection valve 1 according to this embodiment
At 0, the overall behavior is almost the same as the comparative example shown by the broken line, but after local forming after annealing, after quenching,
It can be seen that after further local forming, the fuel leakage was reduced to 以下 or less in comparison with the comparative example, and the oil tightness was improved. That is, as described in the first embodiment, the residual stress is first radiated by annealing after the sheet portion is formed and the orifice is punched out, and the local forming is performed after the radiating. Fuel leakage after molding is reduced (FIG. 12B). In addition, since the residual stress at the time of quenching is limited to the local stress at the time of local forming by the ball 21 by locally applying a stress after the residual stress is released, the residual stress released at the time of quenching is reduced. It is possible to reduce the size, thereby minimizing a decrease in accuracy such as roundness and surface roughness. Therefore, the amount of fuel leakage does not increase so much immediately after quenching (FIG. 12 (C)), and the accuracy can be further recovered by local forming again after quenching to make the value of the amount of leakage extremely small (FIG. 12C). FIG. 12 (D)).

As described above, according to the fuel injection valve 10 of this embodiment, the variation in the amount of fuel injection from the orifice 9 of the nozzle 1 can be reduced, the fuel injection control can be performed with high accuracy, and the engine can be stabilized. The improved fuel supply becomes possible and the engine operability is improved. Further, it is possible to reduce the occurrence of defects in the flow rate adjustment performed after the fuel injection valve 10 is assembled.
Further, since fuel leakage between the valve element 15 and the seat portion 1a is reduced to improve oil tightness and high-precision fuel injection control becomes possible, it is possible to obtain good startability when starting the engine.

[0056]

According to the present invention, since the thickness of the orifice processing portion can be simultaneously formed at the time of forming the concave surface, the step of removing the protruding portion as in the prior art is not required. Therefore, the processing steps of the nozzle can be shortened, the entire manufacturing process can be rationalized, the manufacturing equipment can be simplified, and the productivity can be improved, so that the manufacturing cost can be reduced. Further, since the degree of work hardening of the orifice processed portion can be increased and the work hardening index (n value) of the material is reduced, it is possible to prevent the occurrence of minute dripping at the orifice inlet portion following the concave surface during punching, and to prevent the edge portion from being edged. Can be sharpened very stably. Further, the processing can be easily performed with good reproducibility. Therefore, the influence of the orifice on the flow coefficient of the orifice is reduced and the flow rate supplied by the orifice is stabilized, so that the flow rate can be controlled with high accuracy. When applied to a fuel injection valve, high-precision fuel injection control becomes possible, and stable fuel supply to the engine becomes possible, and engine operability is improved. Further, it is possible to reduce the occurrence of defects in the flow rate adjustment performed after assembling the injection valve.

Further, according to the present invention, since the material is softened by annealing before the local forming, the springback at the time of the local forming is reduced, and the forming can be performed with a low load and high accuracy. Also, at this time, since the magnitude of the residual stress at the time of quenching is extremely small due to annealing and local forming, a great deal of residual stress is released at the time of quenching, and accuracy such as roundness and surface roughness is improved. There is no significant decrease. Therefore, the accuracy of the roundness, the surface roughness, and the like can be improved as compared with the related art, so that the flow rate can be controlled with high accuracy. When the present invention is applied to a fuel injection valve, the oil tightness between the valve body and the valve seat is improved, the fuel injection control with high accuracy can be performed, and good startability at the time of starting the engine can be obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a sheet part forming procedure in a method for manufacturing a nozzle according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing the structure of the nozzle according to the first embodiment of the present invention.

FIG. 3 is a partially enlarged view of the nozzle shown in FIG. 2 ;

FIG. 4 is a longitudinal sectional view showing the structure of a nozzle material.

FIG. 5 is a partially enlarged view of FIG. 1;

FIG. 6 is a longitudinal sectional view showing a procedure for punching an orifice in a method for manufacturing a nozzle.

FIG. 7 is a vertical cross-sectional view showing a local forming processing procedure of a sheet portion in a method of manufacturing a nozzle.

FIG. 8 is a longitudinal sectional view showing the entire structure of an electromagnetic fuel injection valve according to a second embodiment of the present invention.

FIG. 9 is a diagram showing a variation in fuel injection amount to show an orifice supply flow rate stabilizing action of the electromagnetic fuel injection valve.

FIG. 10 is a longitudinal sectional view of a main part showing a structure of a nozzle provided in an electromagnetic fuel injection valve according to a comparative example.

FIG. 11 is a partially enlarged view of FIG. 10;

FIG. 12 is a diagram showing the amount of fuel leakage from the fuel injection valve after each manufacturing process to show the effect of improving the oil tightness of the seat portion of the electromagnetic fuel injection valve.

[Explanation of symbols]

1 Nozzle 1a Sheet part (concave surface) 1b Ring part (extruded part) 1d Lower surface 1e Orifice processing part 2a Bottom part 2b-1 Upper inner wall 2b-2 Lower inner wall 3 Punch 3a Sheet type 3c Stopper part 4a Dice 4b Dice 4c Flat surface 4d Groove 4e Tapered surface 5 Guide 6 Upper slide 7 Knockout pin 8 Stripper 9 Orifice 9a Shear cylindrical surface 9b Edge 10 Electromagnetic fuel injection valve 11 Nozzle material 12 Yoke 13 Core 14 Movable valve 15 Valve body 16 Swirler 17 Spring 18 Female top 18a Supporting part 19 Male top 20 Guide body 21 Ball 23 Punched stub 24 Punch 24a Tip cutting edge 25 Punch guide 26 Die 26a Cutting edge 27 Die guide 28 Stopper 31 Electromagnetic coil 100 Molding device 200 Punching device 300 Part molding apparatus iota ₁ Who addition unit length iota ₂ Who inclusive of the thickness of the length t orifice processing unit

Continuing from the front page (72) Inventor Kenichi Gunji 2477 Kashimayatsu, Kata-shi, Ibaraki Pref. JP-A-56-23337 (JP, A) JP-A-1-166844 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02M 61/18 360 F02M 61/16 F02M 51/06 F16K 31/06-31/11 B21K 1/20-1/22 B21K 21/08

Claims (10)

(57) [Claims] 1. A method for manufacturing a nozzle having an orifice for measuring a fluid, comprising: forming a bottomed cylindrical nozzle material by pressure forming with a forming punch; and forming a substantially conical concave surface provided on an inlet side of the orifice. A first procedure of forming a bottom portion of the nozzle material, and punching with a punch from the concave side,
Forming a second orifice at the bottom of the nozzle blank;
And the first step is to use a molding die and a molding die arranged on the outlet side of the orifice to form a material flowing toward the lower surface of the nozzle by pressure molding. A method of manufacturing a nozzle, comprising: extruding an outer peripheral side; and adjusting a thickness of an orifice processed portion where an orifice is formed by punching in the second procedure to a predetermined dimension. 2. The method according to claim 1, wherein a martensitic stainless steel having a carbon content of 0.25% or more is used as the nozzle material. 3. The method of manufacturing a nozzle according to claim 1, wherein the first step is a step of work hardening the hardness of the orifice processed portion to Hv270 or more. 4. A method of manufacturing a nozzle having an orifice for measuring a fluid, comprising: performing a press forming process on a bottomed cylindrical nozzle material with a forming punch; and forming a substantially conical concave surface provided on an inlet side of the orifice. A first procedure of forming a bottom portion of the nozzle material, and punching with a punch from the concave side,
Forming a second orifice at the bottom of the nozzle blank;
And annealing the nozzle material with the orifice formed therein, and locally applying a local forming punch to the seat portion with the valve body of the concave surface that has been micro-deformed by recrystallization of stress strain due to plastic deformation due to the annealing. A third step of quenching the nozzle material which has been subjected to the local pressure forming after performing the pressure forming, and wherein the first step comprises performing the pressure forming to the lower surface of the nozzle. Orifice forming the orifice by punching out the material flowing toward the outer periphery of the orifice with the forming punch and the forming die arranged on the outlet side of the orifice. A method of adjusting a thickness of a portion to a predetermined size. 5. A nozzle provided with an orifice for measuring a fluid, comprising: a substantially conical concave surface provided at an inlet side of the orifice and formed by press forming from an inlet side of the orifice; An orifice provided at an outlet side of the orifice, and an extruded portion formed by being extruded from an inlet side of the orifice to an outer peripheral side of the orifice, wherein the orifice is punched from an inlet side of the orifice. A sharp edge portion formed by the method described above and a shearing cylindrical surface following the edge portion, the nozzle being formed to have a predetermined length in the flow direction by the extrusion process. 6. A nozzle provided with an orifice for measuring a fluid, wherein a substantially conical shape as a sheet portion is provided on an inlet side of the orifice .
It has a concave surface, and this concave surface is formed by pressure forming from the inlet side of the orifice, and after being annealed, is subjected to local pressure forming from the inlet side of the orifice to correct the sheet portion shape. is, and further tempering is performed, said orifices, before the concave is subjected to annealing, followed by the edge portion and the edge portion formed by being stamped from the inlet side of the orifice shear A nozzle having a cylindrical surface. 7. A nozzle provided with an orifice for measuring a fluid, wherein the orifice is provided at an inlet side of the orifice, formed by pressure forming from the inlet side of the orifice, and annealed after being annealed. A substantially conical concave surface in which the shape of the sheet portion has been modified by being locally press-formed from the inlet side of the orifice and further quenched, and provided at the outlet side of the orifice, and the outer periphery of the orifice from the inlet side of the orifice The orifice has an extruded portion formed by being extruded to the side, and the orifice is formed by being punched from the entrance side of the orifice before the concave surface is annealed. It is provided with an edge portion having a shape and a shearing cylindrical surface following the edge portion, and is formed to have a predetermined length in a flow direction by the extrusion process. Nozzles characterized by. 8. A valve body which is operated by an electromagnet, a valve seat accommodating the valve body and constituting a valve, and a nozzle provided with an orifice provided downstream of the valve seat. A fuel injection valve that opens and closes the valve to inject fuel from the orifice, wherein the nozzle is provided at an inlet side of the orifice, and is formed substantially by pressure molding from the inlet side of the orifice. A conical concave surface, and an extruded portion provided on an outlet side of the orifice and formed by being extruded from an inlet side of the orifice to an outer peripheral side of the orifice; and the orifice has an inlet of the orifice. An extruding process comprising a sharp edge formed by punching from the side and a shearing cylindrical surface following the edge. A fuel injection valve, characterized in that it is formed more predetermined flow path direction length. 9. A valve body which is operated by an electromagnet, a valve seat accommodating the valve body and constituting a valve, and a nozzle provided with an orifice provided downstream of the valve seat. A fuel injection valve that opens and closes the valve to inject fuel from the orifice, wherein the nozzle has a seat on the inlet side of the orifice.
Has a substantially conical concave Te, the concave surface, the is formed by the inlet side of the orifice is machined pressing, it is localized pressing process from the inlet side of the orifice after being subjected to annealing The shape of the sheet portion has been corrected, and further quenching has been performed.The orifice has an edge portion formed by punching from the entrance side of the orifice before the concave surface is annealed. A fuel injection valve having a shear cylindrical surface following the edge portion. 10. A valve body which is operated by an electromagnet, a valve seat accommodating the valve body and constituting a valve, and a nozzle provided with an orifice provided downstream of the valve seat. In the fuel injection valve that opens and closes the valve to inject fuel from the orifice, the nozzle is provided on the inlet side of the orifice, and is formed by being press-formed from the inlet side of the orifice, and is annealed. After being subjected to a local press forming process from the inlet side of the orifice, the shape of the sheet portion is corrected, and furthermore, a substantially conical concave surface which is quenched and provided on the outlet side of the orifice, And an extruded portion formed by being extruded from the entrance side to the outer peripheral side of the orifice, wherein the orifice has the concave surface annealed. A sharp edge formed by punching from the inlet side of the orifice and a shearing cylindrical surface following the edge, and being formed to a predetermined length in the flow direction by the extrusion. A fuel injection valve.