JP2010185318A - Lift amount adjusting device for fuel injection valve and lift amount adjusting method to be used for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lift amount adjusting method for a fuel injection valve, whereby a high quality fuel injection valve with its injection amount property less varied with respect to each product can be obtained. <P>SOLUTION: The lift amount adjusting method for the fuel injection valve includes a step of comparing the lift amount of a needle 70 before adjusted with a standard value for a predetermined lift amount and determining a target adjusting amount for the lift amount to be adjusted, a step of determining welding conditions corresponding to the target adjusting amount in accordance with a relationship among the target adjusting amount, the welding conditions, and a lift variation in welding with a change of the welding conditions, and a step of welding a body 20 to a housing 90 to form a welded portion corresponding to the determined welding conditions. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lift amount adjusting method for a fuel injection valve and a lift amount adjusting device used in the method.

  A fuel injection valve as disclosed in Patent Document 1 is known as a fuel injection valve for supplying fuel to an internal combustion engine.

  This fuel injection valve is formed in a cylindrical shape, a fuel passage through which fuel flows from the base end to the tip is formed inside, and a body hole in which a nozzle hole communicating with the fuel passage is formed at the tip. A movable core that is accommodated in the fuel passage so as to be reciprocally movable; a needle that is attached to the movable member and is seated on the inner wall of the fuel passage so as to control fuel injection from the nozzle hole; While being seated on the inner wall of the fuel passage, it is fixed to the inner wall of the fuel passage closer to the proximal end than the movable core so as to have a predetermined gap between the movable core and the movable core is moved toward the proximal end. A fixed core that limits and determines the lift amount of the needle.

  According to this Patent Document 1, a method of adjusting the clearance between the movable core and the fixed core and adjusting the lift amount of the valve member by adjusting the fixed position of the fixed core with respect to the body is adopted. The fixed core is fixed by welding after being press-fitted into the body.

Japanese Patent No. 4158348

  However, when the lift amount is adjusted by the adjustment method as described above, the injection amount characteristic varies and the quality of the fuel injection valve is deteriorated. The body and the fixed core are relatively large components among the components constituting the fuel injection valve. For this reason, when these parts are manufactured, the manufacturing variation is larger than components having a smaller physique than these parts. For this reason, the press-fit load at the time of press-fitting components having large manufacturing variations greatly varies. Here, the press-fitting load is a load applied to the press-fitted article when the press-fitted article is press-fitted into the press-fitted article.

  In order to increase the manufacturing efficiency of the fuel injection valve, the press-fitting and fixing position of the fixed core with respect to the body is adjusted by the load applied when the fixed core is press-fitted and the time to apply the load. By doing so, it is not necessary to measure the moving amount of the press-fitting device one by one with the measuring device, and the time spent for the fixing process of the fixed core can be shortened.

  However, since the press-fit load varies as described above, the method of adjusting the lift amount of the valve member by adjusting the press-fit fixing position of the fixed core has a limit in increasing the adjustment accuracy of the lift amount. In the fuel injection valve described above, the fixed core is press-fitted and fixed to the body and then firmly fixed by welding. If the fixed core is fixed to the body by welding, thermal distortion occurs around the welded area, the lift amount changes, and the injection amount characteristics of each product vary.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to lift a fuel injection valve capable of obtaining a high-quality fuel injection valve in which variation in injection quantity characteristics among products is suppressed. It is to provide a quantity adjustment method.

  Another object of the present invention is to provide a lift amount adjusting device used in a lift amount adjusting method for a fuel injection valve, which can obtain a high quality fuel injection valve in which variations in injection amount characteristics among products are suppressed. .

The invention according to claim 1 is formed in a cylindrical shape, and a fuel passage for flowing fuel from the base end side toward the tip is formed inside, and an injection hole communicating with the fuel passage is formed at the tip. A valve member that moves back and forth in the fuel passage so as to be separated from the fuel passage and controls the opening and closing of the nozzle hole, and is provided on the base end side of the valve member, and restricts the movement of the valve member to the base end side. A lift member of a valve member of a fuel injection valve, comprising: a body that accommodates a stopper portion; and an annular member that is formed in a cylindrical shape and is provided so as to surround an outer peripheral wall of the body and is fixed to the body by welding. A lift amount adjustment method to be adjusted,
The target adjustment amount that determines the target adjustment amount of the lift amount to be adjusted by comparing the lift amount of the valve member before adjustment after the stopper portion is accommodated in the body with the predetermined standard value of the lift amount of the valve member. A setting step and a welding condition setting step for determining a welding condition for welding the body and the annular member, and the valve member when welding is performed by changing the predetermined target adjustment amount and the welding condition and the welding condition. Welding the body and the annular member so as to form a welding condition setting step for setting a welding condition according to the target adjustment amount based on the relationship with the amount of change in lift and a weld according to the determined welding condition And a welding process.

  This invention is an invention characterized in that the shrinkage of the welded portion that occurs after the welding process is used as a driving force for deforming the member.

  According to this invention, in the welding condition setting step, the relationship between the target adjustment amount determined in the target adjustment amount setting step and the lift change amount of the valve member when welding is performed by changing the welding condition and the welding condition; Based on the above, the welding conditions corresponding to the target adjustment amount are determined. And in a welding process, a body and an annular member are welded so that the welding part according to the determined welding conditions may be formed.

  When the welding of the body and the annular member is completed through such a process, the welded portion that has been melted is cooled and starts to contract by itself. Due to the shrinkage of the welded portion, the inner diameter of the annular member is reduced. Here, it is known that the shrinkage of the welded portion changes depending on welding conditions such as the size of the welded portion and the amount of heat applied. Therefore, the reduction amount of the inner diameter of the annular member changes according to the welding conditions.

  Since the inner diameter of the annular member is reduced, the body receives a compression load corresponding to the reduction amount. The body that has received the compressive load corresponding to the reduction amount tends to maintain its own volume, and thus extends in the axial direction. This extension amount is an amount corresponding to the compression load.

  When the body extends by an amount corresponding to the compression load, a gap formed between the stopper portion and the valve member in a state where the valve member is seated in the fuel passage changes by an amount corresponding to the amount of expansion of the body. Along with this, the lift amount of the valve member also changes.

  When the body and the annular member are welded, the lift amount of the valve member changes through the above-described process. Therefore, the lift amount of the valve member can be freely adjusted by adjusting the welding conditions.

  According to this invention, since the welding conditions corresponding to the target adjustment amount are determined, the lift amount of the valve member can be brought as close as possible to the standard value by welding the body and the annular member under the welding conditions.

  Further, in the present invention, since the welding condition is determined after the stopper portion is accommodated in the body, and the lift amount of the valve member is adjusted by welding the body and the annular member based on the welding condition, the manufacturing variation of the stopper portion. In addition, the mounting accuracy of the stopper portion, or the influence of thermal distortion when the stopper portion is attached to the body does not reach the lift amount of the adjusted valve member. That is, the lift amount of the valve member can be accurately adjusted regardless of the state of the stopper portion.

  Therefore, by adjusting the lift amount of the valve member in this way, it is possible to suppress the variation in the lift amount for each product, and provide a fuel injection valve in which the variation in the injection amount characteristic for each product is suppressed. It is.

  In welding technology, one of the welding conditions to be defined is the amount of heat input to the welding location. It is known that the amount of shrinkage of the weld after welding is changed by changing the amount of heat input. Here, the heat input is the amount of heat per unit length given to the weld.

  The invention according to claim 2 is characterized in that the welding condition is an amount of heat input when the welded portion is formed. According to the present invention, the heat input is set as a welding condition. For this reason, the shrinkage amount of the welded portion after welding can be controlled by controlling the heat input amount.

  Thereby, since the reduction amount of the internal diameter of an annular member can be controlled, the compression load to a body can be controlled and the expansion amount to the axial direction of a body can be controlled. Therefore, the lift amount of the valve member can be adjusted by setting the heat input amount as a welding condition.

  In the welding technology, one of the welding conditions to be determined is a welding speed when forming a welded portion. It is known that by changing the welding speed, the amount of heat input applied to the welded portion changes, and the shrinkage amount of the welded portion after welding changes.

  The invention according to claim 3 is characterized in that the welding condition is a welding speed at the time of forming the welded portion. According to this invention, the welding speed is the welding condition. For this reason, the shrinkage amount of the welded portion after welding can be controlled by controlling the welding speed.

  Thereby, since the reduction amount of the internal diameter of an annular member can be controlled, the compression load to a body can be controlled and the expansion amount to the axial direction of a body can be controlled. Therefore, the lift amount of the valve member can be adjusted by setting the welding time as a welding condition.

  In welding technology, one of the welding conditions to be determined is the output of a heat source when forming a weld. It is known that by changing the output of this heat source, the amount of heat input applied to the welded portion changes, and the amount of shrinkage of the welded portion after welding changes.

  The invention described in claim 4 is characterized in that the welding condition is an output of a heat source when forming the welded portion. According to this invention, the output of the heat source when welding is used as the welding condition. For this reason, the shrinkage amount of the welded portion after welding can be controlled by controlling the output of the heat source.

  Thereby, since the reduction amount of the internal diameter of an annular member can be controlled, the compression load to a body can be controlled and the expansion amount to the axial direction of a body can be controlled. Therefore, the lift amount of the valve member can be adjusted by setting the output of the heat source as a welding condition.

  In the welding technique, there is a length of a welded portion to be formed as one of welding conditions to be determined. It is known that the amount of shrinkage of the welded portion after welding changes by changing the length of the welded portion.

  The invention according to claim 5 is characterized in that the welding condition is a circumferential length of the welded portion. According to this invention, the circumferential length of the welded portion is used as a welding condition. For this reason, the shrinkage amount of the welded part after welding can be controlled by controlling the circumferential length of the welded part.

  Thereby, since the amount of reduction of the inner diameter of the annular member can be controlled, the compression load on the body can be controlled, and the amount of expansion of the body in the axial direction can be controlled. Therefore, the lift amount of the valve member can be adjusted by setting the circumferential length of the welded portion as a welding condition.

  The invention described in claim 6 is characterized in that, in the welding step, the welded portion is continuously formed over the entire circumference in the outer peripheral wall of the annular member.

  According to this invention, since the welded portion is continuously formed over the entire circumference of the outer peripheral wall of the annular member, the inner peripheral wall of the annular member is uniform toward the axis of the annular member after the welding process is completed. Can be moved to. For this reason, the bias of the compressive load which an annular member gives to a body can be suppressed, and the precision of lift amount adjustment can be improved.

  The invention described in claim 7 is characterized in that, in the welding process, a plurality of weld portions having substantially the same circumferential length are formed at substantially the same interval on the outer peripheral wall of the annular member.

  According to the present invention, a plurality of welds are formed on the outer peripheral wall of the annular member. However, since the welds are formed at substantially equal intervals, a plurality of welds are formed. However, when the welded portion contracts, the bias of the compressive load imparted to the body by the annular member can be suppressed, and the accuracy of lift amount adjustment can be improved.

  The invention according to claim 8 is characterized in that the welded portion is formed on the tip side of the stopper portion. According to this invention, since the welded portion is formed on the tip side of the stopper portion, the body between the stopper portion and the valve seat portion can be extended in the axial direction, and the stopper portion and the valve member The gap can be changed reliably.

  The invention according to claim 9 is characterized in that a sliding portion on which the outer peripheral wall of the valve member slides is formed on the inner wall of the fuel passage, and the welded portion is formed at a place other than the sliding portion. .

  According to this invention, since the welded portion is formed on the tip side of the stopper portion and at a place other than the sliding portion, the compression load from the annular member acts on the body, and the body is on the inner peripheral side. Even if it is distorted, the movement of the valve member in the axial direction is not hindered. Thereby, the movement of the axial direction of a valve member is securable.

The invention described in claim 10 is a lift amount adjusting device used in the lift amount adjusting method of the fuel injection valve described in claim 1,
A measuring device that measures the lift amount of the valve member before adjustment after the stopper portion is accommodated in the body, and a welding device that welds the body and the annular member so as to form a weld according to a predetermined welding condition. Storing means for storing the relationship between the lift change amount of the valve member when the body and the annular member are welded under different welding conditions and welding conditions, and the standard value of the lift amount of the valve member, and the measuring device Welding conditions for welding the target adjustment amount setting means for determining the target adjustment amount of the lift amount to be adjusted, and the body and the annular member, by comparing the lift amount of the valve member before adjustment measured in step 1 and the standard value The relationship between the target adjustment amount and the amount of change in lift of the valve member when the body and the annular member are welded while changing the welding conditions stored in the storage means and the welding conditions. Based on the target adjustment amount. A welding condition setting means for determining the welding conditions, and a control unit that generates a command signal according to the welding conditions determined by the welding condition setting means and sends the command signal to the welding apparatus. It is characterized by.

  According to the present invention, the control unit compares the standard value of the lift amount of the valve member stored in the storage unit with the lift amount before adjustment measured by the measurement unit in the target adjustment amount setting unit, Define the target adjustment amount. Then, the control unit changes the lift adjustment amount of the valve member when the body and the annular member are welded by changing the welding condition and the welding condition stored in the storage means by the welding condition setting means. The welding conditions corresponding to the target adjustment amount are determined based on And a control part produces | generates the command signal according to this defined welding conditions, and sends the command signal to a welding apparatus. The welding apparatus that has received the command signal operates to form a welded part that satisfies the welding condition defined by the control part, and welds the body and the annular member.

  As described above, since the body and the annular member are welded under the welding conditions corresponding to the target adjustment amount, as described in the operation effect of claim 1, the amount of expansion in the axial direction of the body is arbitrarily adjusted. The lift amount of the valve member can be as close as possible to the specified value.

  In welding technology, one of the welding conditions to be defined is the amount of heat input to the welding location. It is known that the amount of shrinkage of the weld after welding is changed by changing the amount of heat input.

  Here, the heat input is the amount of heat per unit length given to the weld.

  The invention according to claim 11 is characterized in that the welding condition is an amount of heat input when forming the welded portion. According to the present invention, the heat input is set as a welding condition. For this reason, the shrinkage amount of the welded portion after welding can be controlled by controlling the heat input amount.

  Thereby, since the reduction amount of the internal diameter of an annular member can be controlled, the compression load to a body can be controlled and the expansion amount to the axial direction of a body can be controlled. Therefore, the lift amount of the valve member can be adjusted by setting the heat input amount as a welding condition.

  In the welding technology, one of the welding conditions to be determined is a welding speed when forming a welded portion. It is known that by changing the welding speed, the amount of heat input applied to the welded portion changes, and the shrinkage amount of the welded portion after welding changes.

  The invention according to claim 12 is characterized in that the welding condition is a welding speed when forming the welded portion. According to this invention, the welding speed is the welding condition. For this reason, the shrinkage amount of the welded portion after welding can be controlled by controlling the welding speed.

  Thereby, since the reduction amount of the internal diameter of an annular member can be controlled, the compression load to a body can be controlled and the expansion amount to the axial direction of a body can be controlled. Therefore, the lift amount of the valve member can be adjusted by setting the welding time as a welding condition.

  In welding technology, one of the welding conditions to be determined is the output of a heat source when forming a weld. It is known that by changing the output of this heat source, the amount of heat input applied to the welded portion changes, and the amount of shrinkage of the welded portion after welding changes.

  The invention as set forth in claim 13 is characterized in that the welding condition is an output of a heat source when forming the welded portion. According to this invention, the output of the heat source when welding is used as the welding condition. For this reason, the shrinkage amount of the welded portion after welding can be controlled by controlling the output of the heat source.

  Thereby, since the reduction amount of the internal diameter of an annular member can be controlled, the compression load to a body can be controlled and the expansion amount to the axial direction of a body can be controlled. Therefore, the lift amount of the valve member can be adjusted by setting the output of the heat source as a welding condition.

  In the welding technique, there is a length of a welded portion to be formed as one of welding conditions to be determined. It is known that the amount of shrinkage of the welded portion after welding changes by changing the length of the welded portion.

  The invention according to claim 14 is characterized in that the welding condition is a circumferential length of the welded portion. According to this invention, the circumferential length of the welded portion is used as a welding condition. For this reason, the shrinkage amount of the welded part after welding can be controlled by controlling the circumferential length of the welded part.

  Thereby, since the amount of reduction of the inner diameter of the annular member can be controlled, the compression load on the body can be controlled, and the amount of expansion of the body in the axial direction can be controlled. Therefore, the lift amount of the valve member can be adjusted by setting the circumferential length of the welded portion as a welding condition.

It is sectional drawing which shows the whole structure of the fuel injection valve by 1st Embodiment of this invention. It is sectional drawing which shows the principal part of the fuel injection valve shown in FIG. It is a block diagram which shows the outline of the lift amount adjustment apparatus which adjusts the lift amount of the needle in the fuel injection valve shown in FIG. 1 and FIG. It is a flowchart which shows the procedure which performs lift amount adjustment using the lift amount adjustment apparatus shown in FIG. 6 is a graph showing the relationship between the amount of heat input and the amount of change in needle lift. It is the graph which showed the relationship between the circumferential direction length of a welding part, and the lift variation | change_quantity of a needle. It is a block diagram which shows the outline of the lift amount adjustment apparatus by 2nd Embodiment.

  Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. In addition, the overlapping description is abbreviate | omitted by attaching | subjecting the same code | symbol to the component corresponding in each embodiment.

(First embodiment)
First, the structure of the fuel injection valve 10 that is the target of lift amount adjustment will be described with reference to FIG.

(Basic configuration)
FIG. 1 is a cross-sectional view showing the overall structure of the fuel injection valve 10. A fuel injection valve 10 shown in FIG. 1 is an injection valve mounted on a direct injection gasoline engine. The fuel injection valve 10 may be mounted not only on the direct injection gasoline engine but also on a port injection gasoline engine, a diesel engine, or the like. When mounted on a direct injection gasoline engine, the fuel injection valve 10 is mounted on a cylinder head (not shown). The fuel injection valve 10 includes a body 20, a needle 70, an electromagnetic actuator 80, and the like.

  The body 20 is formed in a rod shape and holds functional parts necessary for fuel injection control. A fuel passage 21 through which fuel flows from the base end side toward the tip end is formed inside the body 20. An injection hole 22 communicating with the fuel passage 21 is formed at the tip of the body 20.

  The needle 70 is installed in the fuel passage 21 of the body 20 so as to be reciprocally movable. By intermittently connecting the fuel passage 21, the opening and closing of the injection hole 22 is controlled, and the injection of fuel from the injection hole 22 is controlled. . When the needle 70 is separated from the inner wall of the fuel passage 21, the fuel passage 21 is opened and fuel is injected from the injection hole 22. When the needle 70 is seated on the inner wall of the fuel passage 21, the fuel passage 21 is blocked and fuel injection from the injection hole 22 is stopped.

  The electromagnetic actuator 80 is an actuator that is attached to the body 20, generates power by switching between energization and non-energization, and reciprocally moves the needle 70 with the generated power. When the electromagnetic actuator 80 is energized, the electromagnetic actuator 80 moves the needle 70 to the proximal end side and causes the needle 70 to be separated from the inner wall of the fuel passage 21. By stopping energization of the electromagnetic actuator 80, the electromagnetic actuator 80 moves the needle 70 to the distal end side and seats the needle 70 on the inner wall of the fuel passage 21.

  Hereinafter, each element will be described in detail.

  The body 20 includes a pipe 30, a nozzle holder 40, a nozzle body 50, and the like. The pipe 30, the nozzle holder 40, and the nozzle body 50 are all formed in a cylindrical shape, and are assembled so that the axis of each element is arranged on one axis.

  The pipe 30 is a metal cylindrical member having an inner diameter that is substantially the same in the axial direction. The pipe 30 forms a part of the fuel passage 21 inside. The pipe 30 has a magnetic portion 31 and a nonmagnetic portion 32 from the proximal end side toward the distal end side. The magnetic part 31 and the nonmagnetic part 32 are integrally connected by, for example, laser welding. The pipe 30 may be formed by magnetizing or demagnetizing a part of the cylindrical object by heat processing or the like. Further, the pipe 30 may be formed of only a magnetic material, and the cross-sectional area at the position corresponding to the non-magnetic portion 32 may be made smaller than other portions.

  An inlet member 100 is installed at the proximal end of the pipe 30. The inlet member 100 is connected to a fuel pipe (not shown) and introduces fuel into the fuel passage 21. In the present embodiment, the fuel whose pressure is increased to 4 MPa to 20 MPa is introduced into the inlet member 100 through the fuel pipe. The inlet member 100 is fixed to the pipe 30 by being press-fitted into the inner wall of the pipe 30 and then being welded. The inlet member 100 has a filter 101 that catches foreign substances contained in the fuel. In addition, an O-ring 102 that fills the gap between the fuel pipe and the fuel pipe is provided on the outer peripheral side of the inlet member 100.

  A nozzle holder 40 is installed at the end of the pipe 30 on the tip side. The nozzle holder 40 is formed in a cylindrical shape from a magnetic material. The inner diameter of the base end side of the nozzle holder 40 is substantially the same as the inner diameter of the pipe 30. The nozzle holder 40 is fixed to the pipe 30 by welding or the like.

  The inner diameter on the distal end side of the nozzle holder 40 is smaller than the inner diameter on the proximal end side. A nozzle body 50 is installed at the end of the nozzle holder 40 on the front end side. The nozzle holder 40 and the nozzle body 50 form a part of the fuel passage 21 inside. The fuel passage 21 formed by the pipe 30 and the fuel passage 21 formed by the nozzle holder 40 and the nozzle body 50 communicate with each other.

  The nozzle body 50 is a cylindrical member having a bottom, and is fixed to the inner wall of the nozzle holder 40 by either press fitting or welding, or by welding after press fitting. The bottom part of the nozzle body 50 forms a conical surface whose inner diameter becomes smaller toward the tip. A valve seat 51 on which the needle 70 is seated is formed on the conical surface. An injection hole 22 is formed in the conical surface on the tip side of the valve seat 51. The nozzle hole 22 communicates with the fuel passage 21.

  The needle 70 includes a main body portion 71, a valve portion 72, and a restriction portion 73. The needle 70 is formed in a rod shape from a metal material, and is installed on the axis of the pipe 30, the nozzle holder 40 and the nozzle body 50 so as to be reciprocally movable.

  The valve portion 72 is provided at an end portion on the distal end side of the main body portion 71 and has a shape that can be seated on the valve seat 51 from the proximal end side. When the valve portion 72 is separated from the valve seat 51, the fuel passage 21 is opened, the fuel passage 21 and the injection hole 22 communicate with each other, and fuel is injected from the injection hole 22. When the valve portion 72 is seated on the valve seat 51, the fuel passage 21 is shut off, the communication between the fuel passage 21 and the injection hole 22 is cut off, and the fuel injection from the injection hole 22 is stopped.

  The restriction portion 73 is a portion that is provided at an end portion on the proximal end side of the main body portion 71 and protrudes radially outward from the main body portion 71. The restricting portion 73 can come into contact with a contact portion 83 of the movable core 81 described later, and is a portion that restricts relative movement between the movable core 81 and the needle 70.

  A communication passage 74 is formed in the main body portion 71 and the restriction portion 73 to connect the fuel passage 21 formed in the pipe 30 portion and the fuel passage 21 formed in the nozzle holder 40 portion. The communication passage 74 extends in a radial direction from the first series passage 75 extending along the axial center line of the needle 70 from the end portion on the base end side of the restriction portion 73 to the middle of the main body portion 71, and A second communication path 76 that communicates the first series path 75 and the outer wall of the main body 71 is provided. As a result, the fuel introduced from the inlet member 100 into the fuel passage 21 in the pipe 30 portion flows into the fuel passage 21 in the nozzle holder 40 portion via the communication passage 74.

  The electromagnetic actuator 80 includes a movable core 81, a coil 87, a fixed core 88, a first spring 91, a second spring 92, a housing 90, an upper housing 95, and the like.

  The movable core 81 is formed in a cylindrical shape from a magnetic material, and is disposed between the restriction portion 73 and the valve portion 72 of the needle 70 so as to be reciprocally movable inside the pipe 30 and the nozzle holder 40. In the movable core 81, the outer wall of the movable core 81 is slidably in contact with the pipe 30 and the inner wall of the nozzle holder 40. Thereby, the movable core 81 can reciprocate in the axial direction within the pipe 30 and the nozzle holder 40. The inner wall of the pipe 30 and the nozzle holder 40 is formed with a sliding portion 43 on which the outer wall slides when the movable core 81 reciprocates in the axial direction.

  The movable core 81 has a support hole 82 that supports the needle 70 so as to be relatively movable at the center. The inner diameter of the support hole 82 is larger than the outer diameter of the main body 71 of the needle 70 and smaller than the outer diameter of the restricting portion 73. As a result, the needle 70 can reciprocate in the axial direction within the movable core 81.

  In addition, the movable core 81 has a contact portion 83 at the proximal end that restricts relative movement in a direction in which the needle 70 and the movable core 81 are separated from each other by contacting the restriction portion 73. In a state where the valve portion 72 of the needle 70 is seated on the valve seat 51, the movable core 81 can be relatively moved on the tip side with respect to the restricting portion 73. Even when the restricting portion 73 of the needle 70 comes into contact with the contact portion 83 of the movable core 81, when the movable core 81 moves to the proximal end side, the needle 70 moves to the proximal end side together with the movable core 81. As a result, the valve portion 72 of the needle 70 is separated from the valve seat 51.

  The coil 87 is formed by rotating an electric wire around the bobbin shaft center on the outer periphery of a bobbin which is a resin-made cylindrical member, and generates a magnetic field by energizing the electric wire. The coil 87 is installed outside the pipe 30. The end of the electric wire is connected to the terminal 111 of the connector 110 provided on the proximal end side of the coil 87. The terminal 111 is electrically connected to an external control device, and the coil 87 is energized through the terminal 111.

  The fixed core 88 is formed in a cylindrical shape from a magnetic material, and is installed on the proximal end side of the movable core 81. The fixed core 88 is fixed to the inner wall of the pipe 30 by press fitting or the like. In the present embodiment, the fixed core 88 is firmly fixed by welding after being press-fitted into the inner wall of the pipe 30. A vertical hole 89 extending in the axial direction is formed at the center of the fixed core 88. The vertical hole 89 allows the fuel introduced from the inlet member 100 to flow.

  In the present embodiment, as shown in FIG. 1, the inlet member 100, the vertical hole 89 of the fixed core 88, and the needle 70 are disposed on the axis of the pipe 30, the nozzle holder 40, and the nozzle body 50.

  A first spring 91 is installed on the proximal end side of the restricting portion 73 of the needle 70. The first spring 91 is a spring that is wound spirally around a linear elastic material, and is accommodated in the vertical hole 89 of the fixed core 88. An end portion on the distal end side of the first spring 91 is supported by a seat portion 77 formed at an end portion on the proximal end side of the restriction portion 73.

  The proximal end of the first spring 91 is supported by a cylindrical adjuster pipe 113 that is press-fitted into the vertical hole 89. The first spring 91 is disposed between the restricting portion 73 and the adjuster pipe 113 in a state where the first spring 91 is compressed in the axial direction, and the needle 70 and the movable core 81 are moved away from the fixed core 88, that is, the valve. The part 72 is pressed in the direction in which the valve seat 51 is seated. Hereinafter, the direction in which the valve portion 72 is seated on the valve seat 51 is referred to as the valve closing direction, and the opposite direction is defined as the valve opening direction.

  A second spring 92 is installed on the tip side of the movable core 81. The second spring 92 is a spring spirally wound around a linear elastic material, and is accommodated in the nozzle holder 40.

  The nozzle holder 40 is formed in the inner wall of the nozzle holder 40 so as to be recessed toward the distal end side, and an accommodation recessed portion 41 having a seat portion 42 that supports the end portion on the distal end side of the second spring 92 at the bottom portion. I have. The housing recess 41 is formed in a cylindrical shape, and the inner diameter of the housing recess 41 is substantially the same as or larger than the outer diameter of the second spring 92. For this reason, the movement of the second spring 92 in the radial direction is restricted by the side wall of the housing recess 41. The base end side end of the second spring 92 is supported by a seat portion 85 formed at the bottom of the recess 84 formed in the movable core 81.

  The recessed portion 84 is formed so as to be recessed toward the fixed core 88 from the end portion on the distal end side of the movable core 81. The recess 84 is formed in a cylindrical shape, and the inner diameter thereof is larger than the inner diameter of the housing recess 41. The second spring 92 is disposed between the concave portion 84 of the movable core 81 and the accommodating concave portion 41 of the nozzle holder 40 while being compressed in the axial direction, and presses the movable core 81 toward the fixed core 88.

  Here, the pressing force of the first spring 91 is larger than the pressing force of the second spring 92. For this reason, when the coil 87 is not energized, the needle 70 and the movable core 81 are always pressed in the valve closing direction by the first spring 91. At this time, the contact portion 83 of the movable core 81 is in contact with the restricting portion 73 of the needle 70 by the pressing force of the second spring 92.

  The fuel that has flowed into the inlet member 100 flows into the communication passage 74 of the needle 70 via the vertical hole 89 of the fixed core 88 and the adjuster pipe 113. The fuel that has flowed into the communication path 74 is discharged from the second communication path 76 to the fuel path 21 in the nozzle holder 40 portion outside the needle 70 and reaches the nozzle hole 22.

  The housing 90 is formed of a magnetic material into a cylindrical shape, and is installed outside the pipe 30 and the nozzle holder 40. The inner diameter of the housing 90 is larger than the outer diameters of the pipe 30 and the nozzle holder 40 and is large enough to form a gap between the housing 90 and the pipe 30 and the nozzle holder 40. A coil 87 is installed in the formed gap.

  The length of the housing 90 in the axial direction is large enough to straddle the nonmagnetic portion 32 of the pipe 30. The end portion on the front end side of the housing 90 is fixed to the nozzle holder 40 by laser welding or the like.

  FIG. 2 shows a main part of the fuel injection valve 10 shown in FIG. As shown in FIG. 2, the end portion on the front end side of the housing 90 is formed in a cylindrical shape and is an annular portion 90 a that is installed so as to surround the outer peripheral wall of the nozzle holder 40.

  A press-fit portion 90c into which the outer peripheral wall of the nozzle holder 40 is press-fitted is formed on the inner peripheral wall of the annular portion 90a. Furthermore, it has the welding part 90d formed by welding by laser welding, after press-fitting and fixing the press-fit part 90c to the outer peripheral wall of the nozzle holder 40 in the intermediate part of the annular part 90a.

  The welded portion 90d is continuously formed over the entire circumference in the outer peripheral wall 90b of the annular portion 90a by a welding apparatus 140 described later. The welded portion 90d is formed by heat input from the outer peripheral wall 90b of the annular portion 90a by the welding device 140 and melting a portion of the annular portion 90a and the nozzle holder 40.

  As shown in FIG. 1 and FIG. 2, the welded portion 90 d is formed on the tip side of the fixed core 88 and in a place other than the sliding portion 43 formed on the inner peripheral wall of the nozzle holder 40 or the pipe 30. Has been.

  As shown in FIG. 1, the upper housing 95 is formed in a disk shape from a magnetic material. A part of the upper housing 95 is notched, and a part of the connector 110 is disposed in the notched part. The upper housing 95 is installed on the proximal end side of the coil 87, and the outer peripheral side is in contact with the housing 90 and the inner peripheral side is in contact with the magnetic part 31 of the pipe 30.

  Here, when the coil 87 is energized, a magnetic field corresponding to the direction of the current flowing through the wire of the coil 87 is generated inside and outside the coil 87. When a magnetic field is generated around the coil 87, magnetic flux flows through the fixed core 88, the movable core 81, the nozzle holder 40, the housing 90, the upper housing 95, and the magnetic part 31, and a magnetic circuit is formed. When the magnetic circuit is formed, a magnetic attraction force that is a force by which the fixed core 88 attracts the movable core 81 is generated between the fixed core 88 and the movable core 81.

  The configuration of the fuel injection valve 10 has been described above. Next, the operation of the fuel injection valve 10 will be described.

  When the coil 87 is energized, a magnetic attractive force is generated between the fixed core 88 and the movable core 81. The sum of the magnetic attraction force and the pressing force of the second spring 92 is the pressing force of the first spring 91, the needle pressing force toward the distal end due to the fuel pressure, the weight of the movable core 81, and the movable core 81 and the pipe 30. When the sum of the sliding resistance forces becomes larger, the movable core 81 moves toward the fixed core 88. At this time, since the contact portion 83 of the movable core 81 is in contact with the restriction portion 73 of the needle 70, the needle 70 also moves together with the movable core 81 toward the fixed core 88, that is, in the valve opening direction.

  As a result, the valve portion 72 of the needle 70 is separated from the valve seat 51. The movement in the valve opening direction moves until the movable core 81 contacts the fixed core 88. At this time, the needle 70 has moved to the maximum lift position. In the present embodiment, the amount of movement of the needle 70 until the valve portion 72 moves away from the valve seat 51 and the movable core 81 contacts the fixed core 88 is defined as the lift amount of the needle 70.

  When the movable core 81 is attracted to the fixed core 88 and the valve portion 72 of the needle 70 is separated from the valve seat 51, the fuel passage 21 and the injection hole 22 communicate with each other, and the fuel in the fuel passage 21 is injected from the injection hole 22. Is done.

  When the coil 87 is switched from the energized state to the non-energized state, no magnetic attractive force is generated between the fixed core 88 and the movable core 81. For this reason, the needle 70 moves in the valve closing direction by the pressing force of the first spring 91. At this time, the contact portion 83 of the movable core 81 is in contact with the restriction portion 73 of the needle 70. Therefore, the movable core 81 also moves in the valve closing direction. Since the needle 70 moves in the valve closing direction, the valve portion 72 is seated on the valve seat 51, the fuel passage 21 is blocked, and fuel is not injected from the injection hole 22.

  Next, a method for adjusting the lift amount of the needle 70 in the fuel injection valve 10 will be described. In the present embodiment, by adjusting the press-fitting and fixing position of the fixed core 88 with respect to the pipe 30, the welding amount 90 d when the housing 90 is welded and fixed to the nozzle holder 40 instead of adjusting the lift amount of the needle 70. The lift amount of the needle 70 is adjusted using the contraction of the needle 70. In the present embodiment, the lift amount is adjusted by the lift amount adjusting device 120 shown in FIG.

  FIG. 3 is a schematic diagram showing a lift amount adjusting device 120 that adjusts the lift amount of the needle 70 in the fuel injection valve 10 shown in FIGS. 1 and 2. FIG. 3 shows a state where the assembly 11 in which most of the components of the fuel injection valve 10 described above are assembled is installed in the lift amount adjusting device 120.

  Here, the assembly 11 is an assembly of components other than the first spring 91, the adjuster pipe 113, the inlet member 100, and the filter 101.

  The lift amount adjusting device 120 includes a measuring device 130, a laser welding device 140, a control unit 150, and the like.

  The measuring device 130 is a device that measures the lift amount of the needle 70 in the assembly 11. The measuring device 130 includes a measuring pin 131, a measuring unit 133, an energizing unit 134, and the like.

  The measurement pin 131 is formed in a rod shape, and is installed in the inlet member 100, the vertical hole 89 of the fixed core 88, and the first series passage 75 of the needle 70. The tip portion 132 of the pin 131 is in contact with the bottom portion of the first series passage 75.

  The measuring unit 133 is a measuring unit that measures the amount of movement of the measuring pin 131 in the axial direction as the lift amount of the needle 70 and sends the result to the control unit 150 electrically connected to the measuring unit 133. The measurement unit 133 is installed at the end of the measurement pin 131 on the proximal end side.

  The energization unit 134 is means for energizing / de-energizing the coil 87. The energization unit 134 is electrically connected to the terminal 111. The energization unit 134 is electrically connected to the control unit 150, and energizes / de-energizes the coil 87 according to a command from the control unit 150.

  The welding device 140 is a device for welding the nozzle holder 40 and the housing 90. The welding apparatus 140 employed in the present embodiment is a laser welding apparatus 140 that uses a YAG laser beam (hereinafter simply referred to as a welding apparatus 140).

  The welding apparatus 140 includes a jig 141, a laser oscillator 142, a transmission unit 143, a condensing unit 144, a gas ejection unit 145, a driving unit 146, and the like.

  The jig 141 supports the assembly 11 when adjusting the lift amount. The jig 141 has an insertion hole 141a into which the distal end side of the assembly 11 can be inserted at the center part and a support part 141b that supports the housing 90 at the peripheral part of the insertion hole 141a.

  The laser oscillator 142 oscillates a YAG laser beam L serving as a heat source for welding. The laser oscillator 142 is controlled by the control unit 150 and oscillates a YAG laser beam L that can obtain a predetermined output corresponding to the welding conditions.

  The transmission unit 143 transmits the YAG laser beam L oscillated by the laser oscillator 142 to the condensing unit 144. Various methods can be used as the transmission unit 143. There are a transmission method using an optical fiber and a transmission method using a mirror.

  The condensing unit 144 is optically connected to the transmission unit 143, condenses the YAG laser beam L transmitted from the transmission unit 143 to an appropriate size with a built-in lens, and is welded. Irradiation toward the portion 90d (see FIGS. 2 and 3).

  The gas ejection part 145 sprays the shielding gas G for suppressing the welding part 90d from being oxidized during welding toward the welding part 90d. The shield gas G to be used is, for example, argon, helium, nitrogen or the like.

  The drive part 146 is a means for driving the jig 141 so that the predetermined welded part 90d is formed. The drive unit 146 rotates the jig 141 so that the axis of the assembly 11 installed on the jig 141 becomes the central axis. The drive unit 146 is controlled by the control unit 150 and rotates the jig 141 at a predetermined rotation speed. In the present embodiment, the drive unit 146 is configured to drive the jig 141, but may be configured to drive the light collecting unit 144 so as to go around the assembly 11.

  The control unit 150 is a means for obtaining a measurement result from the measurement device 130 and controlling the welding device 140 based on the result. The control unit 150 is configured as a microcomputer, and is configured by a known microcomputer including a central processing unit 151, a memory 152, an input / output device 153, and the like.

  The central processing unit 151 generates a command signal for controlling the welding apparatus 140 based on the measurement result from the measurement apparatus 130 and the processing program stored in the memory 152, and sends the generated command signal to the welding apparatus 140. The input / output device 153 is controlled.

  The lift amount adjusting device 120 that adjusts the lift amount of the needle 70 has been described above. Next, the process of adjusting the lift amount of the needle 70 will be described using the flowcharts shown in FIGS. FIG. 4 is a flowchart showing a procedure for adjusting the lift amount using the lift amount adjusting device 120 shown in FIG.

  The lift amount adjustment process consists of three steps.

  The first step is a target adjustment amount setting step. In this step, after the fixed core 88 is fixed to the pipe 30 and accommodated, the lift amount of the needle 70 before adjustment is measured, and the measured lift amount and a predetermined standard for the lift amount of the needle 70 are measured. The target adjustment amount of the lift amount to be adjusted is determined by comparing with the value.

  The second step is a welding condition setting step. In this step, a welding condition for welding the nozzle holder 40 and the annular portion 90a of the housing 90 is determined as a welding condition corresponding to the target adjustment amount.

  The third process is a welding process. In this step, the nozzle holder 40 and the annular portion 90a are welded so as to form a welded portion 90d corresponding to the determined welding conditions.

  Before entering the target adjustment amount setting step, the assembly 11 to be installed on the jig 141 of the lift amount adjustment device 120 is prepared (see FIG. 3).

  In this embodiment, the movable core 81, the needle 70, and the second spring 92 are accommodated in the pipe 30, the nozzle holder 40, and the nozzle body 50 that are joined. Further, the fixed core 88 is press-fitted into the pipe 30 at a predetermined distance from the movable core 81 and welded. At this time, the gap formed between the movable core 81 and the fixed core 88 is smaller than the standard value of the lift amount of the needle 70.

  Then, the inlet member 100 fitted with the O-ring 102 is press-fitted into the pipe 30 and welded. Thereafter, the coil 87 is fitted on the outer peripheral side of the pipe 30 and the nozzle holder 40. Next, the housing 90 is inserted from the distal end side of the coil 87 fitted into the pipe 30 and the nozzle holder 40, and the press-fitting portion 90 c of the annular portion 90 a at the end on the distal end side is press-fitted into the outer peripheral wall of the nozzle holder 40. To do. From the base end side, the upper housing 95 is fitted into the gap between the housing 90 and the pipe 30 (see FIGS. 1 and 2).

  Finally, after the terminal 111 is electrically connected to the coil 87, the connector 110 is formed by insert molding with a resin material. The assembly 11 is created through the steps as described above. The above-described process is an example, and the assembly 11 may be created by other procedures.

(Target adjustment amount setting process)
As shown in FIG. 4, in step S <b> 10 (hereinafter simply referred to as “S <b> 10”, the same applies to other steps), the prepared assembly 11 is placed on the jig 141 as shown in FIG. 3. Then, the tip 132 of the measurement pin 131 is brought into contact with the bottom of the first series passage 75 in the needle 70 through the inlet member 100 and the vertical hole 89 of the fixed core 88.

  The energization unit 134 is connected to the terminal 111. At this time, the energization from the energization unit 134 to the coil 87 is not performed.

  In S <b> 20, the control unit 150 controls the energization unit 134 to energize / de-energize the coil 87. Then, the measurement unit 133 sends the lift amount of the needle 70 to be measured to the control unit 150. The control unit 150 receives information on the lift amount of the needle 70 from the measurement unit 133.

  In S30, the control unit 150 compares the received lift amount information with a preset standard value of the lift amount, and determines a target adjustment amount of the lift amount to be adjusted.

(Welding condition setting process)
After that, in S40, the control unit 150 shows the relationship between the target adjustment amount determined in the process of S30 and the welding conditions and the amount of change in lift as shown in FIGS. A welding condition corresponding to the target adjustment amount is set based on the graph.

  In the present embodiment, the welding condition is either the amount of heat input to the welded portion 90d or the circumferential length of the welded portion 90d to be formed. Here, the heat input is the amount of heat per unit length of the welded portion 90d. With respect to these welding conditions, one condition may be a fixed value and the other condition may be changed, or both conditions may be changed.

  Here, the welding conditions and the amount of change in lift of the needle 70 will be described in detail.

  The annular portion 90a and the nozzle holder 40 installed on the inner side are overlapped, and the laser beam L is irradiated to the place where the welded portion 90d is formed from the outer peripheral wall 90b side of the annular portion 90a, and the light energy of the laser beam L is obtained. When applied to the annular portion 90a, the portion irradiated with the laser beam L generates heat. Then, the portion irradiated with the laser beam L is melted. The melting region reaches the nozzle holder 40 installed inside.

  Then, when the laser beam L is moved at a predetermined speed in the circumferential direction along the outer peripheral wall 90b of the annular portion 90a, the melting region also expands in the circumferential direction.

  When the irradiation of the laser beam L is stopped after melting, the melted portion is cooled and becomes a welded portion 90d. When the welded portion 90d is cooled, a tensile residual stress is generated in the welded portion 90d due to the temperature difference around the welded portion 90d. This tensile residual stress is also generated in the welded portion 90d and its surroundings. This residual stress tends to increase as the area of the welded portion 90d increases. The region of the welded portion 90d depends on the heat input applied from the laser beam L and the circumferential length of the welded portion 90d.

  The inner diameter of the annular portion 90a is reduced according to the residual stress of the welded portion 90d (see the broken line arrow shown in FIG. 2). For this reason, the nozzle holder 40 installed on the inner peripheral side receives a compressive load from the annular portion 90a. The compressive load is a value corresponding to the reduction amount of the annular portion 90a.

  The nozzle holder 40 that has received the compressive load is prevented from deforming in the radial direction, and thus extends in the axial direction in order to maintain its own volume (see the solid arrow shown in FIG. 2). The amount of extension in the axial direction is a value corresponding to the amount of compressive load received by the nozzle holder 40.

  When the nozzle holder 40 extends in the axial direction, the distance between the end of the fixed core 88 on the front end side and the valve seat 51 increases, and the fixed core 88 and the movable core 81 in a state where the needle 70 is seated on the valve seat 51. The gap between and widens according to the amount of extension. As a result, the lift amount of the needle 70 increases by an amount corresponding to the extension amount.

  The lift amount of the needle 70 changes through the process as described above. Since the lift amount has changed through the above-described process, the lift amount of the needle 70 is set to the standard value by adjusting the heat input amount when forming the welded portion 90d or the circumferential length of the welded portion 90d. It can be as close as possible.

  5 and 6 are graphs showing the relationship between the heat input and the lift change amount of the needle 70 and the relationship between the circumferential length of the welded portion 90d and the lift change amount of the needle 70. FIG. As shown in each figure, the relationship between these welding conditions and the amount of change in lift of the needle 70 is a proportional relationship. The relationship as shown in each figure is obtained by an experiment or the like and stored in the memory 152 of the control unit 150.

  As shown in FIGS. 5 and 6, as the heat input or the circumferential length of the welded portion 90d increases, the amount of reduction in the inner diameter of the annular portion 90a increases and the lift change amount of the needle 70 increases.

  Further, as shown in FIG. 5, the amount of heat input is closely related to the welding speed and the output of the laser beam L when forming the welded portion 90d. The amount of heat input can be adjusted by keeping the output of the laser beam L constant and adjusting the welding speed. In this case, the lower the welding speed, the greater the heat input.

  The amount of heat input can also be adjusted by adjusting the output of the laser beam L while keeping the welding speed constant. In this case, the higher the output of the laser beam L, the greater the amount of heat input.

  Therefore, as shown in FIG. 5, the lift amount of the needle 70 can be adjusted by adjusting the welding speed, the output of the laser beam L, and the welding speed. Therefore, the welding speed and the output of the laser beam L can be added as welding conditions.

  In this embodiment, as shown in FIG. 5 and FIG. 6, the welding conditions to be determined are such that the lift amount that can be adjusted by welding falls within a predetermined range.

  As shown in FIG. 5, if the heat input is too low, the welding speed is too fast, or the output of the laser beam L is too low, the bonding strength between the annular portion 90a of the housing 90 and the nozzle holder 40 will give the required strength. It will be lower. As shown in FIG. 6, even if the circumferential length of the welded portion 90d is too short, the bonding strength between the annular portion 90a of the housing 90 and the nozzle holder 40 is less than the required strength.

  On the other hand, as shown in FIG. 5, when the heat input is too high, the welding speed is too slow, or the output of the laser beam L is too high, the weld metal is formed inside the nozzle holder 40 when forming the welded portion 90d. Will melt away. Further, as shown in FIG. 6, the circumferential length of the welded portion 90d is limited by the circumferential length of the outer peripheral wall 90b of the annular portion 90a, and the lift amount cannot be changed any more. The welding conditions must be determined taking these into consideration.

(Welding process)
In S <b> 50, the control unit 150 generates a command signal for operating the welding apparatus 140 so as to satisfy the welding condition defined by the control unit 150, and controls the input / output device to send the signal to the welding apparatus 140.

  This signal is sent from the input / output device of the control unit 150 to the laser oscillator 142, the condensing unit 144, and the driving unit 146. The laser oscillator 142 controls the output of the laser beam L oscillated according to the command signal from the control unit 150. The condensing unit 144 controls the condensing diameter and the like according to a command signal from the control unit 150. Then, the drive unit 146 rotates the jig 141 at a predetermined rotation speed in response to a command signal from the control unit 150.

  Each element 142, 144, 145, 146 cooperates according to a command signal generated based on a welding condition including a heat input amount determined by the control unit 150, a welding speed, and a circumferential length of the welded portion 90d. As a result, the welded portion 90d that satisfies the welding condition is formed in the nozzle holder 40 and the annular portion 90a of the housing 90.

  In this way, the lift amount of the needle 70 after the welding process is adjusted to a predetermined standard value, and the lift amount adjustment is completed.

  In the present embodiment, the lift amount adjustment described above is performed after the fixed core 88 is fixed to the pipe 30. For this reason, the amount of lift of the needle 70 after adjustment of the manufacturing variation of the fixed core 88, the mounting accuracy when the fixed core 88 is press-fitted into the pipe 30, and the thermal distortion caused by welding the fixed core 88 and the pipe 30 are adjusted. It is less than. That is, according to the present embodiment, the lift amount of the needle 70 can be accurately adjusted regardless of the state of the fixed core 88.

  Therefore, if the lift amount of the needle 70 is adjusted by the adjustment method as in this embodiment, the variation in the lift amount for each product can be suppressed, and the fuel injection valve in which the variation in the injection amount characteristic for each product is suppressed can be obtained. Obtainable.

  In addition, according to the present embodiment, the location of the welded portion 90 d to be formed is set to the front end side relative to the end portion on the front end side of the fixed core 88. According to this configuration, after welding, the nozzle body 50 located on the tip side of the fixed core 88 can be extended in the axial direction, and the gap between the fixed core 88 and the movable core 81 can be reliably changed.

  In addition, in this embodiment, since the place of the welded portion 90d to be formed is a place other than the sliding portion 43, even if the annular portion 90a compresses the nozzle body 50 after welding and the nozzle body 50 is distorted to the inner peripheral side. The movement of the movable core 81 in the axial direction is not hindered. Thereby, the movement of the movable core 81 in the axial direction can be ensured.

  Moreover, according to this embodiment, the welding part 90d is continuously formed in the outer peripheral wall 90b of the cyclic | annular part 90a over the perimeter in the welding process. According to this, the inner peripheral wall of the annular portion 90a can be moved uniformly toward the axial center of the annular portion 90a after the welding process is completed. The bias of the compressive load imparted to the nozzle holder 40 by the annular portion 90a after welding can be suppressed, and the accuracy of lift amount adjustment can be improved.

  In the present embodiment, the movable core 81 and the needle 70 correspond to the valve member recited in the claims, and the fixed core 88 corresponds to the stopper portion recited in the claims. Further, the annular portion 90a of the housing 90 corresponds to the annular member described in the claims. Further, the laser beam L corresponds to the heat source described in the claims. The memory 152 corresponds to a storage unit described in the claims.

  In the present embodiment, the process in S30 of the flowchart corresponds to the target adjustment amount setting step and the target adjustment amount setting means described in the claims. And the process in S40 of a flowchart corresponds to the welding condition setting step and the welding condition setting means described in the claims. Furthermore, the process in S50 of the flowchart corresponds to the welding process described in the claims.

(Second Embodiment)
The second embodiment is a modification of the first embodiment. The second embodiment does not measure the lift amount of the needle 70 by operating the needle 70 using the coil 87 included in the assembly 11, but the measurement coil provided in the lift amount adjusting device 120 a. The point of operating the needle 70 using 135 is different from the first embodiment.

  FIG. 7 is a configuration diagram showing an outline of a lift amount adjusting device 120a according to the second embodiment. The assembly 11 in this embodiment is the same as the assembly 11 in the first embodiment.

  Only the parts different from the first embodiment will be described below.

  The lift amount adjustment device 120a of this embodiment includes a measurement coil 135 controlled by the control unit 150 in place of the energization unit 134 of the measurement device 130.

  The measurement coil 135 is installed on the outer peripheral side of the housing 90 of the assembly 11. The measuring coil 135 is controlled by the control unit 150 and energized to generate a magnetic field that generates a magnetic attractive force between the fixed core 88 and the movable core 81. Thereby, the needle 70 can be operated by operating the measuring coil 135 without energizing the coil 87 of the assembly 11, and the lift amount of the needle 70 can be measured.

  The lift amount measurement procedure and the adjustment procedure are the same as the flow described in FIG.

(Other embodiments)
The first and second embodiments of the present invention have been described above. The present invention is not construed as being limited to the above embodiment. The present invention can be applied to various embodiments without departing from the scope of the invention.

  For example, the welded portion 90d may not be formed continuously over the entire circumference of the outer peripheral wall 90b of the annular portion 90a, and a plurality of circumferential lengths that are substantially the same in the outer peripheral wall 90b of the annular portion 90a. The welds 90d may be formed at substantially equal intervals.

  Even in such a welded portion 90d, the lift amount of the needle 70 can be adjusted.

  Further, since the plurality of welded portions 90d are formed at substantially equal intervals, it is possible to suppress the bias of the compressive load applied to the nozzle holder 40 from the annular portion 90a.

  DESCRIPTION OF SYMBOLS 10 Fuel injection valve, 11 Assembly, 20 Body, 21 Fuel passage, 22 Injection hole, 30 Pipe, 40 Nozzle holder, 43 Sliding part, 50 Nozzle body, 51 Valve seat, 70 Needle (valve member), 71 Main part, 72 valve portion, 73 regulating portion, 74 communication passage, 75 first series passage, 76 second communication passage, 80 electromagnetic actuator, 81 movable core (valve member), 87 coil, 88 fixed core, 89 vertical hole, 90 housing, 90a annular part (annular member), 90b outer peripheral wall, 90c press fit part, 90d welded part, 91 first spring, 92 second spring, 95 upper housing, 100 inlet member, 110 connector, 111 terminal, 113 adjuster pipe, 120 lift Quantity adjusting device, 130 measuring device, 131 measuring pin, 133 measuring unit, 134 Current-carrying unit, 140 laser welding device, 141 jig, 142 laser oscillator, 143 transmission unit, 144 condensing unit, 145 gas ejection unit, 146 drive unit, 150 control unit, 151 central processing unit, 152 memory

Claims (14)

It is formed in a cylindrical shape, a fuel passage for flowing fuel from the base end side toward the tip is formed inside, an injection hole communicating with the fuel passage is formed at the tip, and reciprocating movement in the fuel passage And a stopper member that is seated on and off the fuel passage and controls the opening and closing of the nozzle hole, and a stopper portion that is provided on the base end side of the valve member and restricts the movement of the valve member to the base end side. A body that houses
A lift amount adjusting method for adjusting a lift amount of the valve member of the fuel injection valve, comprising: an annular member formed in a cylindrical shape and surrounding the outer peripheral wall of the body and fixed to the body by welding Because
The lift amount of the valve member before adjustment after the stopper portion is accommodated in the body is compared with a predetermined standard value of the lift amount of the valve member, and a target adjustment amount of the lift amount to be adjusted is determined. A target adjustment amount setting step to be determined;
A welding condition setting step for determining a welding condition for welding the body and the annular member, wherein the valve member when welding is performed by changing the determined target adjustment amount, the welding condition and the welding condition. A welding condition setting step for setting a welding condition according to the target adjustment amount based on the relationship with the lift change amount;
A method for adjusting a lift amount of a fuel injection valve, comprising: a welding step of welding the body and the annular member so as to form a weld according to the determined welding conditions.   2. The lift amount adjustment method for a fuel injection valve according to claim 1, wherein the welding condition is a heat input amount when the welded portion is formed.   The method for adjusting the lift amount of the fuel injection valve according to claim 1, wherein the welding condition is a welding speed when forming the welded portion.   The method for adjusting the lift amount of the fuel injection valve according to any one of claims 1 to 3, wherein the welding condition is an output of a heat source when the welded portion is formed.   The lift amount adjustment method for a fuel injection valve according to any one of claims 1 to 4, wherein the welding condition is a circumferential length of the welded portion.   6. The fuel injection valve according to claim 1, wherein in the welding step, the welded portion is continuously formed over the entire circumference of the outer peripheral wall of the annular member. Lift amount adjustment method.   6. The welding process according to claim 1, wherein a plurality of the welded portions having substantially the same circumferential length are formed at substantially the same interval on the outer peripheral wall of the annular member. The lift amount adjustment method of the fuel injection valve described in 2.   The lift amount adjustment method for a fuel injection valve according to any one of claims 1 to 7, wherein the welded portion is formed on a tip side of the stopper portion. A sliding portion on which an outer peripheral wall of the valve member slides is formed on the inner wall of the fuel passage,
9. The lift amount adjustment method for a fuel injection valve according to claim 8, wherein the welded portion is formed at a place other than the sliding portion. A lift amount adjusting device used in the lift amount adjusting method for a fuel injection valve according to claim 1,
A measuring device for measuring a lift amount of the valve member before adjustment after the stopper portion is accommodated in the body;
A welding apparatus for welding the body and the annular member so as to form a weld according to predetermined welding conditions;
Storage means for storing a relationship between a lift change amount of the valve member when welding the body and the annular member under different welding conditions and welding conditions, and a standard value of the lift amount of the valve member; A target adjustment amount setting means for determining a target adjustment amount of the lift amount to be adjusted by comparing the lift amount of the valve member before adjustment measured by the measuring device with the standard value, the body and the annular member, Welding condition setting means for setting welding conditions when welding the body, and welding the body and the annular member while changing the target adjustment amount, the welding conditions and welding conditions stored in the storage means Welding condition setting means for determining a welding condition according to the target adjustment amount based on the relationship with the lift change amount of the valve member at the time, and the welding determined by the welding condition setting means Directive according to conditions No. generate lift amount adjusting device of the fuel injection valve, characterized in that it comprises a control unit to send to the welding device and the command signal.   The lift amount adjusting device for a fuel injection valve according to claim 10, wherein the welding condition is a heat input amount when forming the welded portion.   The lift amount adjusting device for a fuel injection valve according to claim 10 or 11, wherein the welding condition is a welding speed when forming the welded portion.   The method for adjusting the lift amount of the fuel injection valve according to any one of claims 10 to 12, wherein the welding condition is an output of a heat source when forming the welded portion.   The lift amount adjusting method for a fuel injection valve according to any one of claims 10 to 13, wherein the welding condition is a circumferential length of the welded portion.

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