JP2006009706A - Spring retaining member manufacturing method of electromagnetic fuel injection valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture a spring retaining member pressed into a fixed core to stabilize the outer diameter dimension of the spring retaining member and adjust the axial position very accurately, preventing a cutting chip from occurring, in an electromagnetic fuel injection valve where a return spring which urges a valve assembly to the side so as to seat a valve body to a valve seat is compressedly set between the valve assembly where the cylindrical spring retaining member having a slit extending axially and the spring retaining member is pressed into a cylindrical fixed core surrounded by the coil assembly, and a movable core and the valve body opposite to the fixed core are coaxially combined. <P>SOLUTION: There are successively carried out a first process to prepare a bar workpiece 52 having an axially extending groove 51 at the circumference, and extending longer than the spring retaining member 27, a second process to bore the bar workpiece 52 so as to form a coaxialy through-hole 53 opening the inner end side of the groove 51 inside, and a third process to cut off the bar workpiece 52 so as to cut by the length corresponding to the spring retaining member 27. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention provides a cylindrical fixed core surrounded by a coil assembly in which a coil is wound around a bobbin, a single slit extending in the axial direction, and a cylinder having a substantially C-shaped cross section. The valve body is seated on the valve seat between the spring receiving member and a valve assembly in which a movable spring core and a valve body facing the fixed core are coaxially coupled. The present invention relates to an improvement in a manufacturing method for manufacturing the spring receiving member of an electromagnetic fuel injection valve in which a return spring for biasing a valve assembly is contracted.

Such a spring receiving member of the electromagnetic fuel injection valve is press-fitted into the fixed core so that the axial position can be adjusted in order to adjust the spring load of the return spring. For example, Patent Document 1 discloses that a thin plate material made of a rectangular metal is subjected to a rolling process so as to be rounded so as to form a slit extending in the axial direction.
JP-A-4-231672

  However, if the spring receiving member is manufactured by rolling as in the conventional case, the outer diameter accuracy of the spring receiving accuracy may not be stable, and the press-fit load to the fixed core of the spring receiving member may increase. In addition, chips are generated frequently due to the press-fitting, and the position of the spring receiving member is changed due to the spring back, making it difficult to adjust with high accuracy.

  The present invention has been made in view of such circumstances, and manufactures a spring bearing member that is press-fitted into a fixed core so that the outer diameter can be stabilized and the axial position can be adjusted with high accuracy while suppressing the generation of chips. An object of the present invention is to provide a method of manufacturing a spring receiving member in an electromagnetic fuel injection valve.

  In order to achieve the above object, the invention according to claim 1 is characterized in that a cylindrical fixed core surrounded by a coil assembly formed by winding a coil around a bobbin has a single slit extending in the axial direction. A valve assembly in which a cylindrical spring receiving member having a substantially C-shaped cross section is press-fitted, and a movable core and a valve body facing the fixed core are coaxially coupled, and the spring receiving member In the meantime, in manufacturing the spring receiving member of the electromagnetic fuel injection valve in which the return spring for biasing the valve assembly is contracted to the side on which the valve body is seated on the valve seat, a single groove extending in the axial direction is produced. The bar material is perforated so as to form a coaxial through-hole that opens the inner end side of the groove to the inner surface, and a first step of preparing a bar material having an outer periphery and extending longer than the spring receiving member Corresponding to the second step of processing and the spring receiving member. Characterized by sequentially executing the third step of performing processing parting the bar material to cut at a length.

  According to a second aspect of the invention, in addition to the configuration of the first aspect of the invention, in the third step, the chamfering process is cut off so that the chamfered portions are formed on the outer periphery of both ends of the spring receiving member. It is characterized by being applied simultaneously with processing.

  According to the first aspect of the present invention, the bar material prepared with high outer diameter accuracy is subjected to drilling so as to form a coaxial through hole that opens the inner end of the outer circumferential groove to the inner surface. Thus, the outer diameter accuracy of the spring receiving material can be stabilized with high accuracy, and the axial position can be adjusted with high accuracy while suppressing the generation of chips, and the spring receiving member can be press-fitted into the fixed core.

  According to the second aspect of the present invention, the chamfered portion for suppressing the generation of chips when the spring receiving member is press-fitted can be formed on the outer periphery of both end portions of the spring receiving member while avoiding an increase in processing steps.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples of the present invention shown in the accompanying drawings.

  1 to 3 show a first embodiment of the present invention, FIG. 1 is a longitudinal sectional view of an electromagnetic fuel injection valve, FIG. 2 is a perspective view of a spring receiving member, and FIG. 3 is a manufacturing of the spring receiving member. It is a perspective view for demonstrating a process.

  First, referring to FIG. 1, an electromagnetic fuel injection valve for injecting fuel into an engine (not shown) is a valve body which is spring-biased in a direction in which the valve seat 8 has a valve seat 13 at the front end thereof. And a solenoid housing in which a coil assembly 24 capable of exerting an electromagnetic force for driving the valve body 20 on the side separated from the valve seat 13 is connected to the valve housing 8. The solenoid unit 6 accommodated in the coil 25 and the coupler 40 that faces the connection terminals 38 connected to the coil 30 of the coil assembly 24 are integrally provided so that at least the coil assembly 24 and the solenoid housing 25 are embedded. And a covering portion 7 made of synthetic resin.

  The valve housing 8 includes a magnetic cylindrical body 9 formed of a magnetic metal and a valve seat member 10 that is liquid-tightly connected to the front portion of the magnetic cylindrical body 9 by welding in a press-fitted state. The valve seat member 10 is welded to the magnetic cylinder 9 with its rear end fitted to the front end of the magnetic cylinder 9, and the valve seat member 10 opens to the front end surface thereof. A fuel outlet hole 12, a tapered valve seat 13 connected to the inner end of the fuel outlet hole 12, and a guide hole 14 connected to the rear end large diameter portion of the valve seat 13 so as to guide the valve body 20. Are provided coaxially. A steel plate injector plate 16 having a plurality of fuel injection holes 15 leading to the fuel outlet hole 12 is welded to the front end of the valve seat member 10 in a liquid-tight manner.

  The solenoid unit 6 includes a cylindrical movable core 18, a cylindrical fixed core 22 that faces the movable core 18, and a return spring that exerts a spring force that biases the movable core 18 toward the side away from the fixed core 22. 23 and an electromagnetic force that attracts the movable core 18 toward the fixed core 22 against the spring force of the return spring 23 while being arranged so as to surround the rear portion of the valve housing 8 and the fixed core 22. A coil assembly 24 and a solenoid housing 25 surrounding the coil assembly 24 so that the front end portion is connected to the valve housing 8.

  The movable core 18 is slidably fitted to the rear portion of the valve housing 8, and the movable core 18 is coaxial with the valve body 20 that can be seated on the valve seat 13 and close the fuel outlet hole 12. The valve assembly 17 is constructed by being coupled to the valve assembly. In this embodiment, the movable core 18, the valve shaft 19 integrally connected to the movable core 18, and the valve body 20 integrally formed at the front end of the valve shaft 19 constitute a valve assembly 17. In the valve assembly 17, a through hole 21 communicating with the inside of the valve housing 8 is formed coaxially with a bottomed shape with the front end closed, and the valve assembly 17 is a return spring on the side where the valve body 20 is seated on the valve seat 13. 23 is energized.

  The rear end of the magnetic cylinder 9 in the valve housing 8 is coaxially coupled to the front end of the fixed core 22 via a nonmagnetic cylinder 26 formed of a nonmagnetic metal such as stainless steel. The rear end of the body 9 is butt welded to the front end of the nonmagnetic cylindrical body 26, and the rear end of the nonmagnetic cylindrical body 26 is fixed to the fixed core 22 with the front end of the fixed core 22 fitted to the nonmagnetic cylindrical body 26. Welded to.

  The fixed core 22 is integrally formed with an extended cylindrical portion 22c extending rearward from the coil assembly 24, and a spring receiving member 27 is coaxially press-fitted into the fixed core 22. The return spring 23 is interposed between the spring receiving member 27 and the movable core 18. A ring-shaped stopper 28 made of a non-magnetic material is fixed to the inner periphery of the rear end of the cylindrical movable core 18 from the rear end surface of the movable core 18 so as to avoid the movable core 18 coming into direct contact with the fixed core 22. It is press-fitted so as to slightly protrude toward the core 22 side. The coil assembly 24 is formed by winding a coil 30 around a bobbin 29 surrounding the rear portion of the valve housing 8, the nonmagnetic cylindrical body 26 and the fixed core 22.

  The solenoid housing 25 has an annular end wall 31a opposite to the valve portion 5 side end of the coil assembly 24 at one end, and has a cylindrical shape surrounding the coil assembly 24, and is formed of a magnetic metal 31 made of magnetic metal. And a flange portion 22a that protrudes radially outward from the rear end portion of the fixed core 22 and faces the end portion on the opposite side of the valve portion 5 of the coil assembly 24. The flange portion 22a The other end of the magnetic frame 31 is magnetically coupled. In addition, a fitting cylinder portion 31b for fitting the magnetic cylinder body 9 in the valve housing 8 is coaxially provided on the inner periphery of the end wall 31a of the magnetic frame 31, and the solenoid housing 25 is provided with the fitting cylinder portion. The valve housing 8 is connected to the valve housing 8 by fitting the valve housing 8 to 31b.

  A fuel filter 34 is attached to the rear part of the extension cylinder part 22c provided integrally with the rear part of the fixed core 22. In addition, the fixed core 22 and the spring receiving member having the extended cylindrical portion 22 c are provided with a fuel passage 35 coaxially with the through hole 21 of the movable core 18.

  The covering portion 7 fills not only the solenoid housing 25 and the coil assembly 24 but also a part of the valve housing 8 and most of the inlet cylinder 33 while filling the gap between the solenoid housing 25 and the coil assembly 24. The magnetic frame 31 of the solenoid housing 25 is provided with a notch 36 for arranging an arm portion 29a formed integrally with the bobbin 29 of the coil assembly 24 outside the solenoid housing 25. It is done.

  A coupler 40 is integrally provided on the covering portion 7 so as to face the connection terminals 38 connected to both ends of the coil 30 in the coil assembly 24. The base end of the connection terminal 38 is provided on the arm portion 29a. The coil ends 30 a of the coil 30 are welded to the connection terminals 38.

  Incidentally, the covering portion 7 includes a first resin molding layer 7a that covers the solenoid housing 25 and constitutes a part of the coupler 40, and a second resin molding layer 7b that covers the first resin molding layer 7a. The first resin molding layer 7a is not covered with the second resin molding layer 7b and is exposed to the outside from the middle portion of the coupler 40, and the rear portion of the inlet tube 33 is covered with the second resin molding layer 7b. The first resin molding layer 7a is not covered with the second resin molding layer 7b at the portion corresponding to the rear portion of the valve housing 8, and is exposed to the outside. Thus, the first resin molding layer 7a at the middle portion of the coupler 40 and the portion corresponding to the rear portion of the valve housing 8 has endless engagement grooves 48 for engaging the end portions of the second resin molding layer 7b. 49 is formed, and an endless engagement groove 50 for engaging the end portion of the second resin molding layer 7 b is provided on the outer periphery of the intermediate portion of the inlet tube 33. That is, the end portion of the second covering portion 7 b is engaged with the first covering portion 7 a and the inlet tube 33 in an uneven manner.

  The front end of the nonmagnetic cylindrical body 26 surrounds a part of the movable core 18 and is coaxially coupled to the rear end of the magnetic cylindrical body 9 in the valve housing 8 by butt welding. The front part of the fixed core 22 with the front end facing the rear end of the movable core 18 is fitted and fixed.

  A small-diameter fitting portion 22 b that forms an annular stepped portion 43 facing forward is provided coaxially at the front portion of the fixed core 22, and the small-diameter fitting portion 22 b is formed on the nonmagnetic cylindrical body 26. It is fitted to the rear part of the nonmagnetic cylindrical body 26 until the stepped part 43 comes into contact with the rear end of the nonmagnetic cylindrical body 26 so as to be in close contact with the inner surface of the intermediate part. It is fixed to the magnetic cylinder 26.

  An intermediate portion of the movable core 18 is provided with a guide portion 18a slidably in contact with the inner peripheral surface of the rear portion of the magnetic cylindrical body 9, and the valve body 20 is slidable on the inner peripheral surface of the valve seat member 10, that is, the guide hole 14. There is provided a journal portion 20a to be fitted to.

  In FIG. 2, the spring receiving member 27 is formed in a cylindrical shape having a single slit 27 a extending in the axial direction and a substantially C-shaped cross-sectional shape. As shown in FIG. 3A, the spring receiving member 27 has a first step of preparing a bar material 52 having a single groove 51 extending in the axial direction on the outer periphery and extending longer than the spring receiving member 27. As shown in FIG. 3 (b), the bar material 52 is secondly drilled so as to form a slit 27a by drilling a coaxial through hole 53 that opens the inner end side of the groove 51 to the inner surface. As shown in FIG. 3 (c), the process is performed by sequentially executing the third process of cutting off the bar material 52 so as to cut at a length corresponding to the spring receiving member 27. The

  Moreover, in the bar material 52 prepared in the first step, the outer edge portions 51a and 51a of the outer peripheral groove 51 are rounded in advance, and in the third step, the fixed core 22 is provided on the outer periphery of both end portions of the spring receiving member 27. A chamfering process for forming tapered chamfered portions 54 and 54 for suppressing the generation of chips during press-fitting is performed simultaneously with the parting process.

  Next, the operation of this embodiment will be described. In manufacturing the spring receiving member 27 press-fitted into the fixed core 22 integrally having the extension cylinder portion 22a, the spring has a groove 51 extending in the axial direction on the outer periphery. A first step of preparing a bar material 52 extending longer than the receiving member 27, and a second step of perforating the bar material 52 so as to form a coaxial through hole 53 that opens the inner end side of the groove 51 to the inner surface. And the third step of cutting off the bar material 52 so as to cut with a length corresponding to the spring receiving member 27 are sequentially executed, so that the outer diameter accuracy of the bar material 52 is increased. Accordingly, the outer diameter accuracy of the spring receiving material 27 can be stabilized with high accuracy, and the axial position can be adjusted with high accuracy while suppressing the generation of chips, and the spring receiving member 27 can be press-fitted into the fixed core 22.

  In addition, when the chamfered portions 54 and 54 for suppressing the generation of chips when the spring receiving member 27 is press-fitted on the outer periphery of both end portions of the spring receiving member 27, the chamfering processing is performed simultaneously with the parting-off processing in the third step. Therefore, the chamfered portions 54 and 54 can be formed on the outer periphery of both end portions of the spring receiving member 27 while avoiding an increase in processing steps.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. It is.

It is a longitudinal cross-sectional view of an electromagnetic fuel injection valve. It is a perspective view of a spring receiving member. It is a perspective view for demonstrating the manufacturing process of a spring receiving member.

Explanation of symbols

17 ... Valve assembly 18 ... Movable core 20 ... Valve body 22 ... Fixed core 23 ... Return spring 24 ... Coil assembly 27 ... Spring receiving member 27a ... Slit 29 ... Bobbin 30 ... Coil 51 ... Groove 52 ... Bar material 53 ... Through hole 54 ... Chamfer

Claims (2)

  A cylindrical fixed core (22) surrounded by a coil assembly (24) formed by winding a coil (30) around a bobbin (29) has a single slit (27a) extending in the axial direction and traversed. A cylindrical spring receiving member (27) having a substantially C-shaped surface is press-fitted, and the movable core (18) and the valve body (20) facing the fixed core (22) are coaxially coupled. A return spring (between the valve assembly (17) and the spring receiving member (27)) that biases the valve assembly (17) toward the side on which the valve body (20) is seated on the valve seat (13). 23) In manufacturing the spring receiving member (27) of the electromagnetic fuel injection valve, the groove (51) extending in the axial direction is provided on the outer periphery of the spring receiving member (27) so as to be smaller than the spring receiving member (27). A first step of preparing a long bar material (52) and an inner end of the groove (51); A second step of drilling the bar material (52) so as to form a coaxial through hole (53) that opens to the inner surface, and a length corresponding to the spring receiving member (27). And a third step of subjecting the bar material (52) to a cut-off process, and a method for manufacturing a spring receiving member for an electromagnetic fuel injection valve.   2. The electromagnetic method according to claim 1, wherein in the third step, the chamfering is performed simultaneously with the cut-off process so that the chamfered portion is formed on the outer periphery of both ends of the spring receiving member. A method of manufacturing a spring receiving member for a fuel injection valve.

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