0001]The present invention relates to a hollow composite magnetic member and a method of manufacturing the same, and a fuel injection valve.
Background technique
[0002]In recent years, fuel consumption regulations of the automobile becomes severe, the automobile engine has low fuel consumption is required. For low fuel consumption, the fuel injection valve small injection quantity control of the fuel is essential. In an internal combustion engine such as an automobile, an electromagnetic type fuel injection valve is widely used for driving an electric signal from an engine control unit.
[0003]
　Solenoid coil on the outside of the pipe made of a ferromagnetic material, urging the core to the inside of the pipe, is disposed anchor the valve body is mounted, the valve seat side valve element is under the force of the spring when the valve is closed and it has a structure that is. Magnetic circuit is formed around the solenoid coil by the electromagnetic force pulse voltage is generated is applied to the solenoid coil, an anchor is attracted to the core. As a result, the valve body is opened away from the valve seat, fuel is injected from the tip of the fuel injection valve. The anchor and the core allowed is to concentrate the magnetic flux on opposite sides, in order to generate a suction force to the anchor and the core, a portion of the pipe is required to be a non-magnetic or weakly magnetic in order to suppress magnetic flux leakage.
[0004]
　Above, for nonmagnetic or weakly magnetic of a portion of the pipe, Patent Document 1, ferromagnetic or inserting a non-magnetic thin plate between the ferritic two thin plates of the boundary of the sheet performs joining by laser welding, the thin plate after bonding bending processed into shaped sleeve, a method of performing the laser welding is disclosed a fixed longitudinal boundary of the sleeve.
[0005]
　Further, described above, for nonmagnetic or weakly magnetic of a portion of the pipe, Patent Document 2, a method of supplying a Ni wire is disclosed in the laser irradiation position of the magnetic hollow member made of stainless steel.
CITATION
Patent Literature
[0006]
Patent Document 1: JP-T 2007-515586 Patent Publication
Patent Document 2: JP 2001-87875 JP
Summary of the Invention
Problems that the Invention is to Solve
[0007]
　However, in the method described in Patent Document 1, the ferromagnetic material and After combination joined by fabricating a plurality of thin plates made of a non-magnetic material, it is necessary to bond by bending further sleeve-shaped, many man-hours it is difficult to manufacture becomes necessary. In order to achieve the miniaturization of the injector, the solenoid coil is downsized, it is necessary to reduce the magnetic circuit formed. However, in the method described in Patent Document 1, since there is a limit in reducing the width of the non-magnetic portion of the sleeve (pipe), it is difficult to reduce the size of the injector.
[0008]
　Further, since the pure Ni material is magnetic, necessarily nonmagnetic or weakly magnetized is not achieved by the method disclosed in Patent Document 2. To nonmagnetic or weakly magnetic the processing part, select the proper process conditions, it is also necessary to control the bias of the element composition and concentration of element processing part.
[0009]
　An object of the present invention is to provide a fuel injection valve width having a hollow composite magnetic member and which is smaller in the non-magnetic portion, and is to produce such hollow composite magnetic member in a simple manner.
Means for Solving the Problems
[0010]
　Hollow composite magnetic member of the present invention is a hollow member formed of a ferromagnetic material containing 15 wt% to 18 wt% or less of Cr, has a modified portion in a part thereof, the reforming section includes a Cr of 8 wt% to 18 wt%, and 6.5 wt% to 50 wt% of Ni, the alloy containing.
Effect of the invention
[0011]
　According to the present invention, it is possible to provide a fuel injection valve width having a hollow composite magnetic member and which is smaller in the non-magnetic portion. Further, it is possible to produce such hollow composite magnetic member in a simple manner.
[0012]
　As a result, it is possible to provide a response is higher fuel injection valve opening and closing of the fuel injection valve with respect to the pulse voltage applied to the electromagnetic coil, it can contribute to improved fuel efficiency of an automobile equipped with the fuel injection valve.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013]
It is a longitudinal sectional view showing the Figure 1 fuel injector.
Is a longitudinal sectional view showing the structure of a reformer of the pipe in FIG. 2A] Examples 1 and 3.
It is a cross-sectional view of FIG 2B] FIG 2A.
Is a longitudinal sectional view showing the structure of a reformer of the pipe in FIG. 3A] Examples 2 and 4.
It is a cross-sectional view of FIG. 3B] FIG 3A.
4 is a principle diagram of a vibrating sample magnetometer.
Is a [5] Schaeffler organization chart.
DESCRIPTION OF THE INVENTION
[0014]
　The present invention is, that locally weak magnetizing the pipe made of a ferromagnetic material, and to a fuel injection valve having the same. In other words, the above pipe is largely formed of a ferromagnetic material, a part of the pipe which magnetism has been weakened, but which may also be referred to as the hollow composite magnetic member. That is, the hollow composite magnetic member, means a hollow ferromagnetic member having a partially portion weakened magnetic (ferromagnetic pipe).
[0015]
　By using the above pipe can be manufactured highly responsive fuel injection valve small.
[0016]
　Pipe of this invention, for example, as follows.
[0017]
　Pipe of this invention, the pre-reforming, 1.6 × 10 6 of Ni-containing material on a part of the outer peripheral surface of the pipe of the saturation magnetization value is not less than 1.0T ferromagnetic material in the magnetic field applied A / m while adding, by applying heat from the outside to the addition point of the Ni-containing material to form a reforming portion, 1.6 × 10 6 less than the saturation magnetization value of the reforming unit in the applied magnetic field of a / m is 0.6T it is desirable that.
[0018]
　The pipe has a mixing portion between the pipe and the reforming section of the ferromagnetic material, it is desirable that the longitudinal direction of the width of the pipe of the heat treatment portion of the combined reforming section and mixing section is less than 5 mm.
[0019]
　The shape of Ni-containing material to be added to part of the outer peripheral surface of the pipe, the wire is desirably either powder or coating.
[0020]
　When using a wire to Ni-containing material, the cross-sectional shape of solid or hollow circular, is either elliptical or rectangular, the method of addition, the winding of the part of the pipe outer peripheral surface, or the pipe outer peripheral surface to some continuous feeding.
[0021]
　When using the powder of Ni-containing material, the method of addition is delivered to a part of the pipe outer peripheral surface.
[0022]
　When using a coating on Ni-containing material to form a pre-coating on at least a portion of the outer peripheral surface of the pipe.
[0023]
　Supply of heat from the outside to be used in the reforming of the pipe is preferably performed either by laser irradiation, electron beam irradiation or high-frequency induction heating.
[0024]
　Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, the present invention is not limited to the following embodiments.
[0025]
　[Structure and operation principle of the fuel injection valve]
　FIG 1 is a longitudinal sectional view showing an example of a fuel injection valve.
[0026]
　The fuel injection valve 1 is intended for use in an automotive gasoline engine, injecting fuel toward the inside of the intake manifold, a fuel injection valve for low pressure. Hereinafter, it referred the paper above the fuel injection valve 1 upstream, the paper downward and downstream in FIG.
[0027]
　The fuel injection valve 1, a pipe 2, which are mostly formed of a ferromagnetic material, the core 3 accommodated in the pipe 2, the anchor 4, a valve body 5 which is fixed to the anchor 4, the valve when the valve is closed a valve seat member 7 having a valve seat 6 which is closed by the body 5, the electromagnetic coil 9 for actuating the nozzle plate 8, a valve body 5 in the valve opening direction when energized with a fuel injection hole fuel is injected during the valve opening When, and a yoke 10 to induce magnetic flux lines, the.
[0028]
　Pipe 2, for example, an electromagnetic stainless steel magnetic metal material metal pipe or the like which is formed by the press working such deep drawing, by using a means of grinding or the like, stepped cylinder, as shown in FIG. 1 It is formed at an Jo. Pipe 2 has a large diameter portion 21, a small diameter portion 22 in diameter than the large diameter portion 21 is small, the. Incidentally, the pipe 2 is cross-sectional shape is circular.
[0029]
　The small diameter portion 22, thin wall portion 23 is formed to have thinned portions. The small diameter portion 22 houses a core accommodating portion 24 for accommodating the core 3 on the upstream side of the thin portion 23, the anchor 4 on the downstream side of the thin portion 23, the valve member 11 made of a valve body 5 and the valve seat member 7 valve a member accommodating portion 25, the are separated. The thin portion 23, in a state in which the core 3 and anchor 4 is accommodated in the pipe 2, is formed to surround the gap portion between the core 3 and the anchor 4 (area where the core 3 and the anchor 4 is opposed) there. The core 3 and the anchor 4, face each other through the gap. Moreover, the part and has an inner wall of the pipe 2 so as to face, the thin portion 23 is formed in this portion of the pipe 2, this portion, reforming portion is provided as described below.
[0030]
　The thin portion 23 increases the magnetic resistance between the core housing portion 24 and the valve member accommodating portion 25, and disconnects the core housing portion 24 and the valve member accommodating portion 25 magnetically.
[0031]
　Inside the large diameter portion 21 is formed with a fuel passage 26 to send the fuel to the valve member 11, on the upstream side of the large diameter portion 21 a fuel filter 12 for filtering the fuel.
[0032]
　The core 3 is formed into a cylindrical shape having a hollow portion 31 is press-fitted to the core housing portion 24 of the pipe 2. The hollow portion 31, spring receiving member 32 is accommodated which is fixed by means of press fit or the like. At the center of the spring receiving member 32, a fuel passage 33 penetrating in the axial direction is formed.
[0033]
　Anchor 4 made of a magnetic member, and is fixed by welding to the valve body 5 at its downstream side. Anchor 4 has a large diameter portion 41 having an inner slightly smaller diameter outer diameter than the circumference of the small diameter portion 22 of the pipe 2 on the upstream side, a small-diameter portion 42 smaller in outer diameter than the large diameter portion 41, a.
[0034]
　Inside the large diameter portion 41, a spring accommodating portion 43 is formed. The inner diameter of the spring receiving portion 43 is formed on substantially the same diameter as the inner diameter of the hollow portion 31 of the core 3. The bottom of the spring receiving portion 43, the fuel passage hole 44 is formed a through-hole diameter than the inner periphery is smaller spring receiving portion 43. The bottom of the spring receiving portion 43, the spring receiving portion 45 is provided.
[0035]
　External shape of the valve body 5 has a substantially spherical shape, a fuel passage 51 drilled shaved parallel to the axial direction of the fuel injection valve 1 is provided on the outer peripheral surface.
[0036]
　The valve seat member 7, a substantially conical valve seat 6, the valve body holding hole 71 formed substantially the same as the diameter of the valve element 4 from the valve seat 6 on the upstream side, the upstream side from the valve body holding hole 71 toward the upstream opening 72 formed in the larger diameter, the downstream opening 73 that opens to the downstream side of the valve seat 6, are the formation. The valve seat 6 is formed such that the diameter toward the valve body holding hole 71 to the downstream opening 73 is reduced, the valve element 5 is adapted to sit on the valve seat 6 when the valve is closed. Downstream of the valve seat member 7, the nozzle plate 8 is welded.
[0037]
　Anchor 4 and the valve body 5 is disposed so that it can operate in the axial direction in the pipe 2. Between the spring retainer 45 and the spring receiving member 32 of the anchor 4, the coil spring 13 is provided to bias the anchor 4 and the valve body 5 on the downstream side. The valve seat member 7 is inserted into the pipe 2, and is fixed to the pipe 2 by welding. The upstream portion outer periphery of the pipe 2, O-ring 14 for connection to a pipe of a pump to send the fuel is provided.
[0038]
　The outer periphery of the core 3 of the pipe 2, the electromagnetic coil 9 is arranged. Electromagnetic coil 9 includes a bobbin 91 formed of a resin material, a coil 92 which is wound the bobbin 91 wound, and a. Coil 92 is connected to the electromagnetic coil control device via the connector pin 15.
[0039]
　Yoke 10 has a hollow through-hole, a large diameter portion 101 formed on the upstream side, the diameter 102 in which are formed smaller in diameter than the large diameter portion 101, formed from the medium diameter portion 102 smaller in diameter downstream a small-diameter portion 103 formed on a side, and a. The small diameter portion 103 is fitted on the outer periphery of the valve member accommodating portion 25. The inner peripheral portion of the intermediate-diameter portion 102, the electromagnetic coil 9 is arranged. The inner periphery of the large diameter portion 101, connecting the core 16 is disposed.
[0040]
　Connecting core 16 is formed of a magnetic metal material or the like. By connecting the core 16 and the large diameter portion 101 and the pipe 2 is connected. That is, the yoke 10 and the small diameter portion 103 being connected to the pipe 2 in the large diameter portion 101 is connected pipes 2 and magnetically at both ends of the electromagnetic coil 9. Downstream of the yoke 10, the protector 17 for protecting the tip of the pipe 2 is attached.
[0041]
　When power is supplied to the electromagnetic coil 9 via the connector pin 15 a magnetic field is generated, by the magnetic force of the magnetic field, it opens against the anchor 4 and the valve body 5 to the biasing force of the coil spring 13. Accordingly, the fuel supplied from the pump is injected into the combustion chamber of the engine.
[0042]
　[Reforming method]
　method of manufacturing a pipe includes a step of applying a Ni-containing material in the ferromagnetic material, a step of forming the modified portion by supplying heat to the Ni-containing material.
[0043]
　Figure 2A ~ Figure 3B is a device configuration in which the reforming unit in a part of a pipe of a ferromagnetic material containing 15 wt% to 18 wt% of Cr shows schematically.
[0044]
　Figure 2A, with feeds the wire to the pipe, is a longitudinal sectional view showing a device structure for irradiating a laser beam. Further, FIG. 2B is a transverse sectional view.
[0045]
　Figure 3A is a longitudinal sectional view showing a device structure for irradiating a laser beam in a state wound around the wire to the pipe beforehand. Further, FIG. 3B is its horizontal sectional view.
[0046]
　First, an outline of the device structure will be described with reference to FIGS. 2A and 2B.
[0047]
　As shown in FIG. 2A, apparatus is provided with a condenser lens 183 for adjusting the diameter of the laser beam transmitted from the laser oscillator in the fiber, the processor shield jig 188, a. Processor shield jig 188 has a through-hole, thereby making it possible to irradiate the laser beam 184 passes through the through hole in the pipe 2. Moreover, by inserting the wire 181 into the through-hole, which is to be able to contact the wire 181 to the pipe 2. Further, the pipe 2 is installed so that it can rotate in the direction indicated by the symbol a. Inside the processor shield jig 188 and the pipe 2, it has to be able to supply the shielding gas 186, 187.
[0048]
　When forming the reforming unit 185 to the pipe 2 supplies the shielding gas 186 and 187, along with contacting the wire 181 to the pipe 2, the laser beam 184 is irradiated while rotating the pipe 2, the wire 181 to the pipe 2 for welding. Thus, it is possible to form a reforming portion 185 weakened magnetic part of the pipe 2. Incidentally, the reforming unit 185, which is thinner than the other portions of the pipe 2 (which is thin) is desirable.
[0049]
　Heat supply method from the outside can be used, for example, laser irradiation (the fiber laser having a wavelength of 1070 nm). The laser beam circular transmitted in the fiber of the fiber core diameter 0.1mm from the laser oscillator is irradiated with a laser beam 184 through the condenser lens 183 to the outer peripheral surface of the pipe 2. Using cylindrical lenses in a condenser lens 183, is converted as the shape of the laser beam 184 at the focal position becomes linear (width 5 mm, depth 0.2 mm). Focal Remove length of the laser beam 184 with respect to the outer peripheral surface of the pipe 2 (reforming unit) is set to 0 mm, the outer circumferential surface of the pipe 2 so that the width direction of the laser beam 184 is parallel to the longitudinal direction of the pipe 2 at the focal position irradiated.
[0050]
　During irradiation of the laser beam 184 to the outer peripheral surface pipe 2, for preventing oxidation of the reforming unit 185, using the pipe outer peripheral surface shield gas 186 and the pipe inner peripheral surface shield gas 187. Any shield gas species N 2 is. To enable both shield the outer peripheral surface side and the inner peripheral surface side of the reformer 185 of the pipe 2, using the processor shield jig 188.
[0051]
　As heat supply method from outside, in addition to the laser irradiation may be used such as electron beam irradiation, high-frequency induction heating.
[0052]
　In Figures 2A and 2B, the pipe 2 is rotated in the direction of symbol a with a predetermined speed, feeding continuously to the outer circumferential surface of the pipe 2 the wire 181 at a predetermined speed feeds, shielding gas 186 and the pipe inner pipe outer peripheral surface the face shield gas 187 a laser beam 184 is irradiated to the outer peripheral surface of the wire 181 and the pipe 2 while passing a predetermined amount to form a reforming portion 185.
[0053]
　In Figures 3A and 3B, performs the tack fixed by winding a pre-wire 182 to the outer peripheral surface of the pipe 2, after which the pipe 2 is rotated in the direction of symbol a with a predetermined speed, shielding gas 186 and pipe outer peripheral surface a pipe inner peripheral surface shielding gas for 187 laser beam 184 is irradiated to the outer peripheral surface of the wire 181 and the pipe 2 while passing a predetermined amount to form a reforming portion 185.
[0054]
　Pipe 2 is formed of a ferritic stainless steel is a ferromagnetic material. The composition of the pipe 2, which has the following 18 wt% to 15 wt% of Cr in addition to Fe is desirable. Examples of such a metal, for example, a Cr 16.49 mass%, the Si 0.44 wt%, a Ni 0.19 wt%, the C 0.01 mass%, containing 0.25 wt% of Mn thing, and the like.
[0055]
　Was added Ni-containing material in the thin portion 23 (shown in Figure 1) having an outer peripheral surface of the pipe 2 carries out the reforming. Against the portion to modify the Ni-containing material, by supplying heat, it can be modified. A step of applying a portion of reforming the Ni-containing materials, supplying heat may be simultaneous, or may be provided separately.
[0056]
　The Ni-containing materials, for example, can be used pure Ni materials. As another example, for example, there are austenitic stainless steels such as JIS SUS310S steel or JIS SUS316 steel.
[0057]
　The shape of the Ni-containing materials, for example, FIGS. 2A and 2B wires 181 cross-sectional shape of a solid circular as, as shown in Figure 3A and 3B, the cross-sectional shape using the real wire 182 medium in a rectangular shape can. The Ni-containing materials other shapes can be used such as a powder form, coatings like. Examples of film-like ones, for example, there is an electroplating film or cold spray film. The cold spray film is a film formed by the method of spraying a high-speed 300 ~ 1200 m / s the metal gas and 1 ~ 50 [mu] m, and alloys or polymers or mixtures thereof as a jet.
[0058]
　Wire, compared to the Ni-containing material other shapes, while there is an advantage of easily added to the reforming unit 185, there is a limit to the selection of the additive element. Powder, compared with Ni containing material other shapes, there are infinite combinations in the formulation concentration and blending component is an additive element and the concentration can be arbitrarily selected, it added inefficient, further increases the cost. Coating, compared to other Ni-containing material, as with the powder, there are infinite combinations in the formulation concentration and blending components, it can be arbitrarily selected additive element and concentration. However, of the film, the plating film has problems in adhesion to (pipe 2 in the present invention) matrix, and in cold spray film has a problem in uniformity of the film thickness, uniformity of reforming the heat supply unit it is disadvantageous in terms of gender.
[0059]
　When using a wire to Ni-containing material, the cross-sectional shape can be used solid or hollow circle, an ellipse, one of the rectangles and the like.
[0060]
　In terms of manufacturing a wire, the cross-sectional shape is circular or rectangular solid are common, easily available. In particular, a circle of solid are common and can be reduced most cost. Also in terms of the addition to the reforming section 185, the most it added easy with a solid circle. Hollow circles, upon addition, it is disadvantageous in that the uniformity of the reforming unit. Rectangle, warpage is likely to occur as compared to the circle of the solid. Therefore, in the solid circle added by feeding wire, added by winding wire into the pipe 2 in the rectangle is the preferred method.
[0061]
　In the case of using a form of powder of Ni-containing material, the cross-sectional shape is either solid or hollow, the addition method is characterized by delivering to a portion of the pipe outer peripheral surface.
[0062]
　In terms of powder production, solid powder in the same manner as the wire is common, easily available. Also in view of the addition of the reforming unit 185, a stable manner towards in solid than hollow, porosity also hardly generated in the reforming portion 185.
[0063]
　When using a coating on Ni-containing material to form a pre-coating on at least a portion of the outer peripheral surface of the pipe. In the step of applying a Ni-containing material into the ferromagnetic material, the coating is formed on at least a portion of the outer peripheral surface of the pipe. It can be a reforming unit by supplying heat by a laser or the like after forming the film.
[0064]
　The coating may be formed by an electric plating method or a cold spray method.
[0065]
　Against a member having a Ni only to the extent reforming Either method for laser irradiation, in this case using the modification method, including mixing unit consisting of reformer and heat-affected zone around the pipe longitudinal width of the pipe in the heat treatment section may be less than 5 mm. Can minimize the extent of the reforming unit, it can be the width of the non-magnetic portion to produce a small pipe.
[0066]
　[Saturation magnetization and the evaluation method of the element concentration]
　Figure 4, a vibrating sample magnetometer 190 used in the evaluation of the saturation magnetization in this embodiment (hereinafter, referred to as VSM (Vibration Sample Magnetometer).) Illustrates the principle of a.
[0067]
　In VSM, using shakers 191, by oscillating the sample 192 with a minute amplitude, the time variation of the magnetic flux caused by the magnetization of the sample is detected as an induced electromotive force in the detection coil 193 of the sample near the induced electromotive it can be measured magnetization of the sample from the power. Since the induced electromotive force is weak, it is possible to measure the magnetization with high sensitivity by passing a lock-in amplifier 194.
[0068]
　Saturation magnetization value, cutting out a reforming portion 185 of the pipe 2 shown in FIG. 2A, etc., the magnetization curve of the reformer unit 185 is measured using a VSM, a magnetic field is 1.6 × 10 6 magnetization when the A / m it is obtained as a value. Incidentally, the saturation magnetization value of before modification of the pipe 2 is 1.6 T. Saturation magnetization value can be less than 0.6T by a reforming process.
[0069]
　Evaluation of element concentration is cut so that the cross section of the reforming section 185 along the longitudinal direction of the pipe 2 is obtained by using a energy dispersive X-ray scanning electron microscope accessories. Element concentration are those in the cross section of the reforming unit 185, obtained by analyzing the concentration of Cr and Ni in the region 5 places 100μm angle chosen arbitrarily. For example, for the 5 region selected arbitrarily divided into 100μm square in cross-section in the reformer unit, the standard deviation of the Cr concentration is preferably the standard deviation of 1 or less and Ni concentration is 5 or less. If the weak magnetizing of the reforming section 185 has been performed properly, respectively Cr concentration and the Ni concentration is about 10 wt%, from about 30 to 50 mass%. Bias of element concentration of the reforming unit 185, affects the magnetic properties of the reforming section 185. Therefore, it is preferable to suppress the standard deviation of each element to the extent 1/10 of the element concentration in order magnetic properties of the modified portion is uniform and therefore, the standard deviation of the Cr concentration and the Ni concentration, respectively 1 or less, and preferably 5 or less.
[0070]
　[Organization Chart stainless steel]
　FIG 5 is a Schaeffler organization chart, one of the organization chart of stainless steel. From the relationship between the Cr equivalent and Ni equivalent of Schaeffler organization chart, we can predict material structure for element concentration of Cr and Ni in the reforming unit 185.
[0071]
　Ferritic stainless steels used in the present embodiment, Cr equivalent is 17.15, Ni equivalent is 0.615. Considering the dilution of the constituent elements of the ferritic stainless steel with Ni added, the appearance of austenite is tissue of weakly magnetic by modification is recognized, Ni concentration in the reforming unit 185 is 6.5 mass% or more it is the case of. Further, from the results of Examples and Comparative Examples described later, for weak magnetizing is, Ni concentration of the reforming section 185 shall not exceed 50 wt%. In the reforming portion 185, when the Ni concentration is 50 mass%, Cr concentration is 8% by mass. Furthermore, Cr concentration of austenitic stainless steel is non-magnetic material is about 18 wt%. Considering the above, the present invention is to limit the concentration range of Cr and Ni.
[0072]
　Hereinafter, a description will be given of an embodiment.
Example 1
[0073]
　As shown in FIGS. 2A and 2B, the pipe 2 rotates in the direction of a, a circular wire 181 is the cross-sectional shape of the solid with pure Ni material, the thin portion 23 (FIG. 1 with the outer circumferential surface of the pipe 2 while feeding added to shown), a laser beam 184 is irradiated to the outer peripheral surface and the wire 181 of the pipe 2, to form a modified portion. 940W output of the laser beam 184, the rotational speed of 1500 mm / min of the pipe 2, the feed rate 800 mm / min of the wire 181, the feed time of the wire 181 861msec, 1076msec the irradiation time of the laser beam 184, the pipe outer peripheral surface the flow rate of the use shielding gas 186 sets 20L / min, the flow rate of the pipe inner peripheral surface shield gas 187 to 10L / min was reformed. Only the cutting reforming unit 185 and the measurement results of the saturation magnetization was 0.09T. The average value of the element concentration in the cross section of the reforming section 185 along the longitudinal direction of the pipe 2, Cr is 10.2 mass%, Ni was 38.5 wt%. Further, the standard deviation of the element concentration is, Cr is 0.171, Ni was 1.03.
[0074]
　According to this embodiment, before modification saturation magnetization value can be reduced to about 94% relative to the further variation of the inside reforming section 185 of the elemental concentrations of Cr and Ni is reduced. Regardless of where the in the reforming portion 185, so that could be stably reduced saturation magnetization. In other words, it is possible to easily weakly magnetized by a reduced number of steps the local portion of the pipe 2 made of a ferromagnetic material. Also, if the pipe 2 obtained in this example was mounted on a fuel injection valve 1, it can contribute to the improvement of the responsiveness of the opening and closing of the size and fuel injection valve 1 of the fuel injection valve 1, furthermore, the fuel injection valve 1 can contribute to the improvement of fuel efficiency equipped with a vehicle that.
Example 2
[0075]
　As shown in FIGS. 3A and 3B, the outer circumferential surface of the pipe 2, performs advance wound by tacking secures the rectangular wire 182 of a solid cross-sectional shape with pure Ni material, then the direction of the pipe 2 in a It rotates in the laser beam 184 is irradiated to the outer peripheral surface of the pipe 2 in which the wire 182 is wound to form a reformer. The output of the laser beam 184 800 W, the rotational speed of the pipe 2 1953mm / min, 1359msec the irradiation time of the laser beam 184, the pipe outer peripheral surface shield gas 186 flow rate 20L / min, the pipe inner peripheral surface shield gas 187 It was reformed by setting the flow rate to 10L / min. Only the cutting reforming unit 185 and the measurement results of the saturation magnetization was 0.51T. The average value of the element concentration in the cross section of the reforming section 185 along the longitudinal direction of the pipe 2, Cr is 9.98% by mass, Ni was 35.1 wt%. Further, the standard deviation of the element concentration is, Cr is 0.565, Ni was 3.06.
[0076]
　According to this embodiment, before modification saturation magnetization value can be reduced to about 68% relative to the further variation of the inside reforming section 185 of the elemental concentrations of Cr and Ni is reduced. Regardless of where the in the reforming portion 185, so that could be stably reduced saturation magnetization. In other words, it is possible to easily weakly magnetized by a reduced number of steps the local portion of the pipe 2 made of a ferromagnetic material. Also, if the pipe 2 obtained in this example was mounted on a fuel injection valve 1, it can contribute to the improvement of the responsiveness of the opening and closing of the size and fuel injection valve 1 of the fuel injection valve 1, furthermore, the fuel injection valve 1 can contribute to the improvement of fuel efficiency equipped with a vehicle that.
Example 3
[0077]
　As shown in FIGS. 2A and 2B, the pipe 2 rotates in the direction of a, a circular wire 181 is the cross-sectional shape of the solid with pure Ni material, the thin portion 23 (FIG. 1 with the outer circumferential surface of the pipe 2 while feeding added to shown), a laser beam 184 is irradiated to the outer peripheral surface and the wire 181 of the pipe 2, to form a modified portion. 930W output of the laser beam 184, the rotational speed of 1500 mm / min of the pipe 2, the feed rate of the wire 181 700mm / min, 861msec the feeding time of the wire 181, 1076Msec the irradiation time of the laser beam 184, the pipe outer peripheral surface the flow rate of the use shielding gas 186 sets 20L / min, the flow rate of the pipe inner peripheral surface shield gas 187 to 10L / min was reformed. Only the cutting reforming unit 185 and the measurement results of the saturation magnetization was 0.63T. The average value of the element concentration in the cross section of the reforming section 185 along the longitudinal direction of the pipe 2, Cr 11.6 wt%, Ni was 29.9 wt%. Further, the standard deviation of the element concentration is, Cr is 2.64, Ni was 16.0.
[0078]
　According to this embodiment, the reduction ratio of the saturation magnetization values ​​for pre-reforming was about 61%. Compared to Example 1, a large variation in the inside reformer 185 of element concentration Cr and Ni, depending on the location of in the reformer unit 185, it is understood that the saturation magnetization value is varied. However, in comparison with conventional methods, to provide a fuel injection valve equipped with a small width pipes and the pipes of the non-magnetic portion. Further, it is possible to produce a simple method than the prior art.
Example 4
[0079]
　As shown in FIGS. 3A and 3B, the outer circumferential surface of the pipe 2, performs advance wound by tacking secures the rectangular wire 182 of a solid cross-sectional shape with pure Ni material, then the direction of the pipe 2 in a It rotates in the laser beam 184 is irradiated to the outer peripheral surface of the pipe 2 in which the wire 182 is wound to form a reformer. The output of the laser beam 184 700 W, the rotational speed of the pipe 2 2500mm / min, 1060msec the irradiation time of the laser beam 184, the pipe outer peripheral surface shield gas 186 flow rate 20L / min, the pipe inner peripheral surface shield gas 187 It was reformed by setting the flow rate to 10L / min. Only the cutting reforming unit 185 and the measurement results of the saturation magnetization was 1.01T. The average value of the element concentration in the cross section of the reforming section 185 along the longitudinal direction of the pipe 2, Cr 10.7 wt%, Ni was 29.0 wt%. Further, the standard deviation of the element concentration is, Cr is 4.50, Ni was 25.3.
[0080]
　According to this embodiment, the reduction ratio of the saturation magnetization values ​​for pre-reforming was about 37%. Compared to Example 2, variations in the in the reformer unit 185 of the element concentration of Cr and Ni is increased. However, in comparison with conventional methods, to provide a fuel injection valve equipped with a small width pipes and the pipes of the non-magnetic portion. Further, it is possible to produce a simple method than the prior art.
[0081]
　Table 1 illustrates summarizes the results of Examples 1-4.
[0082]
[Table 1]

DESCRIPTION OF SYMBOLS
[0083]
　1: injector, 2: Pipes, 3: core, 4: anchor, 5: valve body 6: valve seat, 7: a valve seat member, 8: nozzle plate, 9: electromagnetic coil, 10: yoke, 11: valve member 12: fuel filter, 13: coil spring, 14: O-ring, 15: connector pin, 16: connecting core, 17: protector 21 :( pipe) large-diameter portion, 22 :( pipe) small-diameter portion , 23: thin-walled portion, 24: core accommodating portion, 25: valve member accommodating portion, 26 :( pipe) fuel passage 31 :( core) hollow portions, 32: spring receiving member 33 :( core) fuel passage of 41 :( anchor) large-diameter portion, 42 :( anchor) small-diameter portion, 43: spring accommodating portion, 44 :( anchor) fuel passage hole, the 45 :( anchor) spring receiving portion, 51 :( valve body) fuel passage, 71: valve body holding hole, 72: upstream opening, 73: downstream opening, 9 : Bobbin, 92: coil, 101 :( York) large-diameter portion, 102 :( yoke) medium diameter portion, the 103 :( York) small diameter portion, 181: cross section of a solid circular wire, 182 : cross-sectional shape of a solid rectangular shape wire, 183: condenser lens, 184: laser beam 185: reforming unit, 186: shielding gas pipe outer peripheral surface, 187: shielding gas pipe circumference, 188: processor shield jig 190: vibrating sample magnetometer, 191: vibrator, 192: sample 193: detection coil, 194: lock-in amplifier, 195: amplitude sensor, 196: magnetic field sensor, 197: vibration control, 198: preamplifier, 199: magnet.

WE CLAIM

[Claim 1]A hollow member formed of a ferromagnetic material containing 15 wt% to 18 wt% or less of Cr, has a modified portion in a part thereof,
　the reforming unit is 8 wt% or more 18 wt % of Cr and comprises an alloy containing, and 6.5 wt% to 50 wt% of Ni, the hollow composite magnetic member.
[Claim 2]
　Cross-sectional shape is a pipe-like circular, claim 1 hollow composite magnetic member according.
[Claim 3]
　The reformer unit, the standard deviation of the concentration of Cr and Ni in the five regions of 100μm angle arbitrarily selected in a section, the standard deviation of the concentration of Cr is 1 or less, and the concentration of Ni It has a characteristic that the standard deviation is less than 5%, the hollow composite magnetic member according to claim 1 or 2.
[Claim 4]
　The reforming portion has a mixing portion caused by the influence of heat to the site adjacent,
　longitudinal width of the heat treatment unit consisting of the reforming unit and the mixing unit is less than 5 mm, according to claim 3, wherein hollow composite magnetic member.
[Claim 5]
　1.6 × 10 6 saturation magnetization value of the magnetic field applied A / m, the ferromagnetic material is at least 1.0 T, the reforming unit is less than 0.6 T, any one of claims 1 to 4, hollow composite magnetic member according to an item.
[Claim 6]
　A method of manufacturing a hollow composite magnetic member providing a reforming section in a part of the hollow member formed of a ferromagnetic material containing 15 wt% to 18 wt% of Cr,
　the ferromagnetic an Ni-containing material a step of applying the material,
　and a step of forming the reformer to supply heat to the Ni-containing material, method of manufacturing the hollow composite magnetic member.
[Claim 7]
　Supply of the heat of laser irradiation is carried out by electron beam irradiation or high-frequency induction heating method of the hollow composite magnetic member according to claim 6, wherein.
[8.]
　The shape of the Ni-containing material, a wire, a powder or coating method for producing a hollow composite magnetic member according to claim 7 wherein.
[Claim 9]
　Cross-sectional shape of the wire, solid or hollow circle, an oval or rectangular, the production method of the hollow composite magnetic member according to claim 8.
[Claim 10]
　Step of applying the Ni-containing material into the ferromagnetic material, continuously the Ni-containing material to said winding said Ni-containing material to a portion of the outer peripheral surface of the ferromagnetic material, or a portion of the outer peripheral surface of the ferromagnetic material it is intended to feed, method of manufacturing a hollow composite magnetic member according to claim 9, wherein.
[Claim 11]
　The shape of the Ni-containing material is a film,
　in the step of applying the Ni-containing material into the ferromagnetic material,
　the coating is formed on at least part of the outer peripheral surface of the ferromagnetic material, according to claim 8 the method of manufacturing hollow composite magnetic member.
[Claim 12]
　The shape of the Ni-containing material is a powder,
　in the step of applying the Ni-containing material into the ferromagnetic material,
　the powder is formed on at least part of the outer peripheral surface of the ferromagnetic material, according to claim 8 the method of manufacturing hollow composite magnetic member.
[Claim 13]
　And the anchor, a core, has a hollow composite magnetic member according to any one of claims 1 to 5,
　on the inside of the hollow composite magnetic member, the said anchor core and is installed,
　the hollow the reforming unit of the composite magnetic member, said anchor and said cores are arranged so as to surround the region facing the fuel injection valve.