JP2010038111A - Solenoid fuel injection valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stabilize a press-fit joining force at a predetermined value without requiring the press-fit joining parts of a coil housing and a yoke of high dimensional accuracy in a solenoid fuel injection valve. <P>SOLUTION: In this solenoid fuel injection valve, the outer periphery of a coil 33 is covered by the coil housing 34 of a magnetic substance having, at the front end, an inward flange 34a press-fitted to the outer peripheral surface of a magnetic cylinder 4. An annular yoke 35 fitted to the rear end inner peripheral surface of the coil housing 34 is press-fitted to the outer peripheral surface of a fixed core 6. A resin mold layer 45 charged in the inside space of the coil housing 34 while covering the coil housing 34 and the yoke 35 is formed on the outer peripheral surface of a valve housing 2. Plural first and second slits 51, 52 which relieve the press-fit joining forces between the inward flange 34a and the magnetic cylinder 4 and between the yoke 35 and the fixed core 6 and which are filled with the resin mold layer 45 are formed in the inner peripheral surface of the inward flange 34a and the inner peripheral surface of the yoke 35. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electromagnetic fuel injection valve used in a fuel supply system of an internal combustion engine, and in particular, a valve housing includes a valve seat member having a valve seat, and a magnetic cylindrical body connecting a front end portion to the valve seat member. , A non-magnetic collar connected to the rear end of the magnetic cylinder, and a fixed core connected to the rear end of the non-magnetic collar, and a seating direction with the valve seat is provided in the magnetic cylinder. A magnetic plunger that is spring-biased is slidably fitted, and this magnetic plunger is opposed to the suction surface of the fixed core front end, and a coil that can excite this is disposed on the outer periphery of the fixed core. The outer periphery of the coil is covered with a magnetic coil housing having an inward flange press-fitted to the outer peripheral surface of the magnetic cylindrical body, and an annular yoke fitted to the inner peripheral surface of the rear end portion of the coil housing is connected to the outer periphery of the fixed core. Press-fit to the face, valve housing The outer peripheral surface of, One cover the coil housing and the yoke ゝ relates to an improvement of an electromagnetic fuel injection valve comprising forming a resin mold layer satisfying an internal space of the coil housing.

Such an electromagnetic fuel injection valve is already known as disclosed in Patent Document 1 below.
JP 2008-57421 A

  In such an electromagnetic fuel injection valve, the magnetic cylinder body and the inward flange of the coil housing, the magnetic flux transfer between each of the fixed core and the yoke are improved by the press-fit coupling, and the magnetic characteristics are improved. . However, if the press-fit coupling force is excessive during the above-mentioned press-fit coupling, the magnetic cylinder and the fixed core will be distorted, and the magnetic plunger's slidability will be hindered, and the valve opening stroke will be distorted. On the other hand, if it is too small, problems such as a decrease in magnetic flux transferability will be caused. In order to avoid such problems, conventionally, the press-fitting allowance between the press-fitting parts has been accurately made constant and the press-fitting coupling force has been controlled to a predetermined value. A high dimensional accuracy has to be required for the press-fitting joint, which has been an obstacle to reducing the cost of the product.

  The present invention has been made in view of such circumstances, and it is possible to stabilize the press-fitting coupling force at a predetermined value without requiring high dimensional accuracy in the press-fitting coupling part, and to provide an inexpensive and high magnetic characteristic. An object of the present invention is to provide an electromagnetic fuel injection valve.

In order to achieve the above object, according to the present invention, a valve housing is connected to a valve seat member having a valve seat, a magnetic cylindrical body connecting a front end portion to the valve seat member, and a rear end of the magnetic cylindrical body. A non-magnetic collar and a fixed core coupled to the rear end of the non-magnetic collar, and a magnetic plunger that is spring-biased in a seating direction with the valve seat slides within the magnetic cylinder. Freely fitted, this magnetic plunger is opposed to the suction surface of the front end of the fixed core, a coil that can excite this is disposed on the outer periphery of the fixed core, and press-fitted to the outer peripheral surface of the magnetic cylinder at the front end The outer periphery of the coil is covered with a magnetic coil housing having an inward flange, and an annular yoke fitted to the inner peripheral surface of the rear end of the coil housing is press-fitted to the outer peripheral surface of the fixed core. The coil housing One covers the fine yoke ゝ, The electromagnetic fuel injection valve comprising forming a resin mold layer satisfying an internal space of the coil housing,
The inner peripheral surface of the inward flange and the inner peripheral surface of the yoke have a plurality of inner flanges and magnetic cylinders, a plurality of press-fit coupling forces between the yoke and the fixed core are alleviated and filled with the resin mold layer. The first feature is that the first and second cutouts are provided at equal intervals in the circumferential direction.

  According to the present invention, in addition to the first feature, the yoke is press-fitted and coupled to the inner peripheral surface of the coil housing, the press-fitting coupling force to the coil housing is relaxed on the outer peripheral surface of the yoke, and the resin A second feature is that a plurality of notches filled with the mold layer are provided at equal intervals in the circumferential direction.

  According to the first feature of the present invention, at the time of press-fitting coupling between the inward flange and the magnetic cylindrical body, the yoke and the fixed core, each press-fitting coupling force is applied to each inner peripheral surface of the inward flange and the yoke in the circumferential direction. Even if there is a slight error in the press-fitting allowance between the press-fitting joints, the press-fitting joint force at each press-fitting joint is kept substantially constant by relaxing by the plurality of first and second notches formed at equal intervals. As a result, it is possible to ensure good magnetic flux transfer between the magnetic cylinder and the coil housing, and between the fixed core and the yoke without giving large distortion to the magnetic cylinder and the fixed core. Thus, an electromagnetic fuel injection valve having high magnetic characteristics can be provided at a low cost.

  In addition, since the first and second notches are filled with the resin mold layer, when the resin mold layer is formed, the first and second notches serve as passages for the molten resin to fill the inside of the coil housing with the molten resin. After molding, the bonding force between the coil housing and the yoke and the resin mold layer can be strengthened by the anchor effect of the resin portion filling the first and second notches.

  According to the second feature of the present invention, when the yoke and the coil housing are press-fitted and coupled, the press-fitting coupling force is relaxed by the third notch, so that there is some error in the press-fitting allowance between the press-fitted joints. However, the press-fitting coupling force at the press-fitting joint can be kept substantially constant, and as a result, good transfer between the coil housing and the yoke can be achieved without giving large distortion to the coil housing and thus the magnetic cylinder. Therefore, it can contribute to further improvement of the magnetic characteristics of the electromagnetic fuel injection valve.

  In addition, since the third notch is filled with the resin mold layer, when the resin mold layer is formed, the third notch can serve as a passage for the molten resin to promote filling of the molten resin into the coil housing. In addition, after the molding, the bonding force between the yoke and the resin mold layer can be strengthened by the anchor effect of the resin portion satisfying the third notch.

  Embodiments of the present invention will be described below on the basis of preferred embodiments of the present invention shown in the accompanying drawings.

  1 is a longitudinal sectional view of an electromagnetic fuel injection valve according to an embodiment of the present invention, FIG. 2 is an enlarged view of part 2 of FIG. 1, FIG. 3 is an enlarged sectional view taken along line 3-3 of FIG. 4-4 is an enlarged sectional view taken along line 4-4, and FIG. 5 is an exploded perspective view of the coil housing and yoke of the electromagnetic fuel injection valve.

  In FIG. 1, an electromagnetic fuel injection valve I has a front end mounted in a mounting hole 1 provided in an intake passage member P1 of the engine, and can inject gas fuel into the intake passage member P1 during an intake stroke of the engine. it can.

  The valve housing 2 of the injection valve I has a valve seat member 3, a magnetic cylindrical body 4, a non-magnetic collar 5, a fixed core 6 and a fuel inlet cylinder 7 arranged sequentially from the front end side in a coaxial manner so as to be liquid-tight with each other. It is configured to be connected to.

  The valve seat member 3 is made of synthetic resin, and a fuel injection hole 10 is formed at the center thereof. A rear end surface of the fuel injection hole 10 is formed as a flat valve seat 8. The outer periphery of the valve seat member 3 includes a first fitting portion 11 located at the rear end portion of the valve seat member 3, a second fitting portion 12 located at the front end portion of the valve seat member 3, An annular coupling recess 13 is formed between the second fitting portions 12 and 13, and annular first and second seal grooves 14 and 15 are formed on the outer periphery of the first and second fitting portions 12 and 13. Are provided respectively. First and second seal members 16, 17 such as O-rings are mounted in the first and second seal grooves 14, 15, respectively. The front end surface of the second fitting portion 12 is formed as a tapered surface 12a having a large diameter toward the second seal groove 15, and the tapered surface 12a attaches the second seal member 17 to the second seal groove 15. At this time, the diameter of the second seal member 17 is guided to facilitate the mounting.

  On the other hand, on the inner periphery of the magnetic cylindrical body 4, a fitting connection hole 18 is connected from the front end side thereof, and a rear end of the fitting connection hole 18 is connected via an annular step portion 19. A concave portion 20 and a sliding guide hole 21 having a smaller diameter than that of the annular concave portion 20 are provided. A thin caulking tube portion 22 is formed at the front end of the magnetic cylindrical body 4. In the fitting connection hole 18, the second fitting portion 12 of the valve seat member 3 is fitted, and at this time, the first seal member 16 is fitted in close contact with the inner peripheral surface of the fitting connection hole 21. The connecting hole 21 is sealed. The caulking cylinder portion 22 is caulked to the connecting recess 13 side of the valve seat member 3 so that the magnetic cylindrical body 4 and the valve seat member 3 are coupled to each other.

  At that time, the connecting recess 13 receives the leading end portion of the caulking tool and facilitates caulking processing inward in the radial direction of the caulking tube portion 22. Further, between the annular step portion 19 of the magnetic cylindrical body 4 and the rear end surface of the valve seat member 3, the fitting depth of the first fitting portion 11 into the fitting connection hole 18 is restricted to restrict the valve seat 8. An annular shim 23 for adjusting the axial position is inserted and held.

  The second fitting portion 12 of the valve seat member 3 is adapted to be fitted into the mounting hole 1 of the intake passage member P1 of the engine. At this time, the second seal member 17 is fitted to the mounting hole 1. The mounting hole 1 is sealed in close contact with the inner peripheral surface.

  A magnetic plunger 25 is slidably accommodated in the magnetic cylindrical body 4. The magnetic magnetic plunger 25 is configured by integrally connecting a valve portion 26 and a sliding cylinder portion 27 from the front end side in a coaxial manner, and the sliding cylinder portion 27 is slidable in the sliding guide hole 21. And the rear end surface is disposed inside the nonmagnetic collar 5 so as to face the suction surface of the front end of the fixed core 6. The sliding cylinder portion 27 is formed such that the axial support length L by the sliding guide hole 21 is shorter than the outer diameter D.

  An annular recess 28 is formed on the outer periphery of the valve portion 26, and the annular recess 28 defines an annular fuel chamber 36 with the annular recess 20 of the magnetic cylindrical body 4.

  A rubber seating member 29 is baked and coupled to the front end surface of the valve portion 26. The seat member 29 can open and close the fuel injection hole 10 by being seated on or separated from the valve seat 8. A stopper rubber 30 is baked on the rear end surface of the sliding cylinder portion 27, and when the fixed core 6 attracts the magnetic plunger 25, the stopper rubber 30 comes into contact with the front end surface of the fixed core 6, so that the seating member 29 Is separated from the valve seat 8 by a predetermined stroke.

  A coil assembly 31 is disposed on the outer periphery from the magnetic cylinder 4 to the fixed core 6. The coil assembly 31 includes a bobbin 32 fitted to the outer peripheral surface from the magnetic cylinder 4 to the fixed core 6, and a coil 33 wound around the outer periphery of the bobbin 32. A terminal support portion 32a that protrudes rearward and supports the base end of the coupler terminal 47 is integrally formed on the outer peripheral portion of the rear end, and the terminal of the coil 33 is electrodeposited on the coupler terminal.

  A coil housing 34 is disposed on the outer periphery of the coil assembly 31. The coil housing 34 is a magnetic body, and has an inward flange 34 a that is press-fitted to the outer peripheral surface of the magnetic cylindrical body 4 and supports the front end surface of the bobbin 32 at the front end thereof. An annular yoke 35 that is also press-fitted and joined to the outer peripheral surface of the rear end portion of the fixed core 6 and is in contact with the rear end surface of the bobbin 32 is fitted to the inner peripheral surface of the rear end portion. The fitting is also press fit.

  As shown in FIGS. 1, 3, and 5, the inner circumferential surface of the inward flange 34a of the coil housing 34 has a plurality of (three in the illustrated example) first cutouts arranged at equal intervals in the circumferential direction. 51 is provided. These first notches 51 contribute to alleviation of the press-fit coupling force between the inward flange 34a and the magnetic cylindrical body 4. A U-shaped opening 54 extending from the rear end of the body of the coil housing 34 to the vicinity of the inward flange 34 a is provided. The U-shaped opening 54 receives the terminal support portion 32 a of the bobbin 32. It is like that.

  As shown in FIGS. 1, 4 and 5, a plurality of (three in the illustrated example) second notches 52 arranged at equal intervals in the circumferential direction are also provided on the inner peripheral surface of the yoke 35. These second notches 52 contribute to the relief of the press-fit coupling force between the yoke 35 and the fixed core 6.

  Further, a plurality of (two in the illustrated example) third notches 53 and 53 ′ arranged at equal intervals in the circumferential direction are also provided on the outer peripheral surface of the yoke 35. These third cutouts 53 and 53 'are formed wider than the first and second cutouts 51 and 52. In particular, one third cutout 53 has another third cutout. The notch width and depth are larger than 53 ', and the terminal support portion 32a of the bobbin 32 is received.

  As shown in FIGS. 1 to 4, a resin mold layer 45 is formed on the valve housing 2 by injection molding so as to cover the outer peripheral surfaces of the magnetic cylinder 4, the coil housing 34, and the fuel inlet cylinder 7. At this time, the resin mold layer 45 is integrally provided with a coupler 46 which is molded simultaneously with the molding and holds the coupler terminal 47. Further, when the resin mold layer 45 is molded, the molten resin is made of the U-shaped opening 54 and the plurality of first notches 51 of the coil housing 34 and the plurality of second and third notches of the yoke 35. The coil 33 is filled by filling the inner space of the coil housing 34 through 52; 53, 53 ′, and the U-shaped opening 54, the first to third cutouts 51, 52; 'Will be satisfied. Resin portions filling the first cutout 51, the second cutout 52, and the third cutout 53, 53 'are indicated by reference numerals 45a, 45b, and 45c, respectively.

  As shown in FIGS. 1 and 2, the magnetic plunger 25 includes a bottomed vertical hole 37 that ends in front of the front end surface of the valve portion 26 past the sliding cylinder portion 27 in the axial direction from the rear end surface thereof. A plurality of lateral holes 38 communicating with the fuel chamber 36 are provided, and the bottom surface of the vertical hole 37 is formed in a spring seat 39. Therefore, in the magnetic plunger 25, the spring seat 39 is offset from the sliding cylinder portion 27 in the forward direction.

  The fixed core 6 has a hollow portion 6a passing through the center thereof, and a pipe-like retainer 41 communicating between the fuel inlet cylinder 7 and the vertical hole 37 is formed on the inner peripheral surface of the hollow portion 6a. Fit and fasten. At this time, a valve spring 42 is contracted by a coil spring between the retainer 41 and the valve seat 8, whereby the magnetic plunger 25 is urged in the seating direction with the valve seat 8.

  The vertical hole 37 has a small diameter hole 37a that fits from the spring seat 39 to the outer periphery of the front end portion of the rising valve spring 42, has a larger diameter than the small diameter hole 37a, and extends from the rear end of the small diameter hole 37a to the rear end surface of the magnetic plunger 25. A large-diameter hole 37b is formed, and the inner end of the lateral hole 38 is opened in the large-diameter hole 37b. By doing so, a cylindrical gap 43 connected to the lateral hole 38 is defined between the inner peripheral surface of the large-diameter hole 37b and the outer peripheral surface of the valve spring 42. The hollow portion 6a of the fixed core 6 is formed so that the outer periphery of the rear end portion of the valve spring 42 supported by the retainer 41 is fitted.

  The fuel inlet cylinder 7 has a flange 7f at the rear end, and a fuel filter 48 having a flange 48f overlapping the flange 7f is fitted into the fuel inlet 7a at the rear end of the fuel inlet cylinder 7 by press fitting. An annular groove 49 is defined between the flange 7f of the fuel inlet cylinder 7 and the rear end surface of the resin mold layer 45, and a seal member 50 is attached thereto. The seal member 50 comes into close contact with the inner peripheral surface of the fuel inlet cylinder 7 when inserted into the gas fuel distribution pipe P2.

  Next, the operation of this embodiment will be described.

  In the demagnetized state of the coil 33, the magnetic plunger 25 is pressed forward by the urging force of the valve spring 42 to seat the seating member 29 on the valve seat 8. In this state, the gas fuel sent from the gas fuel tank (not shown) to the distribution pipe P2 flows into the fuel inlet cylinder 7 and is filtered by the fuel filter 48, and the pipe-like retainer 41 and the magnetic magnetic plunger 25 are vertically arranged. It waits in the magnetic cylinder 4 through the hole 37 and the lateral hole 38, particularly in the fuel chamber 39.

  When the coil 33 is excited by energization, the magnetic flux generated by the coil 33 sequentially travels through the fixed core 6, the yoke 35, the coil housing 34, the magnetic cylinder 4, and the magnetic plunger 25, and the magnetic plunger 25 becomes the set load of the valve spring 42 by the magnetic force. The stopper core 30 of the magnetic plunger 25 is abutted against the front end surface of the fixed core 6 against the valve seat 8 by being attracted to the fixed core 6 and the opening limit of the seating member 29 with respect to the valve seat 8 is restricted. Then, the gas fuel waiting in the magnetic cylinder 4 passes through the valve seat 8 and is injected from the fuel injection hole 10 into the intake passage member P1 of the engine.

  In such an electromagnetic fuel injection valve I, on the inner peripheral surface of the inward flange 34a of the coil housing 34 and the inner peripheral surface of the yoke 35, the magnetic cylindrical body 4 and the fixed core of the inward flange 34a and the yoke 35 are provided. Since the plurality of first and second cutouts 51 and 52 that alleviate each press-fitting coupling force to 6 are provided at equal intervals in the circumferential direction, each of the inward flange 34a, the magnetic cylindrical body 4, the yoke 35, and the fixed core At the time of press-fitting between, the respective press-fitting coupling forces are alleviated by a plurality of first and second notches 51, 52 formed at equal intervals in the circumferential direction on the inner peripheral surfaces of the inward flange 34a and the yoke 35, Even if there is some error in the press-fitting allowance between the press-fitting joints, the press-fitting coupling force at each press-fitting joint can be kept substantially constant, and as a result, a large distortion is given to the magnetic cylinder 4 and the fixed core 6. Without Magnetic cylinder 4 and the coil housing 34, it is possible to ensure good transfer of magnetic flux between the fixed core 6 and the yoke 35. Thus, the electromagnetic fuel injection valve I having high magnetic characteristics can be provided at low cost.

  In addition, since the first and second cutouts 51 and 52 are filled with the resin mold layer 45, the first and second cutouts 51 and 52 serve as passages for the molten resin when the resin mold layer 45 is molded. Filling of the resin in the coil housing 34 can be promoted, and after molding, the coil housing 34 and the yoke 35 and the resin are formed by the anchor effect of the resin portions 45a and 45b filled with the first and second cutouts 51 and 52. The bonding force between the mold layer 45 and each of the mold layers 45 can be strengthened.

  The yoke 35 is also press-fitted and coupled to the inner peripheral surface of the coil housing 34, and a plurality of third notches 53 and 53 ′ for relaxing the press-fitting coupling force between the yoke 35 and the coil housing 34 are formed on the outer peripheral surface of the yoke 35. Since the yoke 35 and the coil housing 34 are press-fitted and joined at equal intervals in the circumferential direction, the press-fitting coupling force is relaxed by the third notches 53 and 53 ', so that the press-fitting allowance between the press-fitted joints is somewhat Even if there is an error, the press-fitting coupling force at the press-fitting joint can be kept substantially constant. As a result, the coil housing 34 and the magnetic cylinder 4 are not greatly strained, and the coil housing 34 and Good transferability between the yokes 35 can be ensured, which can contribute to further improvement of the magnetic characteristics of the electromagnetic fuel injection valve I. In addition, since the third notches 53 and 53 'are filled with the resin mold layer 45, when the resin mold layer 45 is formed, the third notches 53 and 53' serve as a passage for the molten resin, and the coil housing of the molten resin. 34 can be promoted, and after molding, the bonding force between the yoke 35 and the resin mold layer 45 is enhanced by the anchor effect of the resin portion 45c filling the third notches 53 and 53 '. be able to.

  On the other hand, in the magnetic plunger 25, the spring seat 39 that supports the movable end of the valve spring 42 is offset in front of the sliding cylinder portion 27, that is, on the valve seat 8 side. A centering action is exerted on the sliding cylinder portion 27 by the load of the spring 42, and the magnetic plunger 25 can always be held in a stable posture without tilting. The gas fuel injection characteristics can be stabilized by smoothing the sliding, improving the responsiveness of the magnetic plunger 25, accurately adjusting the timing of the seating member 29 with respect to the valve seat 8. As a result, the axial length L of the sliding cylindrical portion 27 of the magnetic plunger 25 can be set shorter than the outer diameter D thereof, and the axial direction of the electromagnetic fuel injection valve can be shortened. .

  However, according to the test, the axial support length L of the sliding cylindrical portion 27 by the sliding guide hole 21 is approximately ½ of the outer diameter D as shown in the figure. If it is the limit of shortening of the axial direction of the cylinder part 27, and if it is less than that, the sliding stability of the magnetic plunger 25 will fall, and it is not preferable.

  In addition, the front and rear end portions of the valve spring 42 are restrained from moving in the radial direction by the small diameter hole 37a of the magnetic plunger 25 and the hollow portion 6a of the fixed core 6, so that the expansion and contraction posture of the valve spring 42 is stable. In addition, contact with the inner peripheral surface of the large-diameter hole 37b of the valve spring can be prevented.

  Moreover, the inner end of the horizontal hole 38 opens into the large-diameter hole 37b of the magnetic plunger 25, and the cylindrical gap 43 that is continuous with the horizontal hole 38 between the inner peripheral surface of the large-diameter hole 37b and the outer peripheral surface of the valve spring 42. Therefore, the gas fuel that has flowed into the vertical hole 37 flows not only inside the valve spring 42 but also through the cylindrical gap 43 on the outside thereof, and flows into the horizontal hole 38. This can contribute to the reduction of the channel resistance of 37.

  Further, the valve seat member 3 made of synthetic resin is fitted on the outer periphery of the valve seat member 3 at the rear end portion of the valve seat member 3 and fitted in the fitting connection hole 18 at the front end portion of the magnetic cylindrical body 4. Part 11, a second fitting part 12 which is located at the front end of the valve seat member 3 and is fitted into the mounting hole 1 of the intake passage member P1 of the engine, the first and second fitting parts 12, 13 is formed, and the caulking cylinder portion 22 formed at the front end of the magnetic cylindrical body 4 is caulked toward the connecting concave portion 13 so that the magnetic cylindrical body 4 and the valve seat member 3 are coupled to each other. Therefore, the front end portion of the caulking tool can be received in the connecting recess 13 without being interfered with the second fitting portion 12, and the caulking process to the connecting recess 13 side of the caulking tube portion 22 can be easily performed. , The magnetic cylinder 4 and the valve seat member 3 can be reliably coupled. At this time, the first seal member 16 that is in close contact with the inner peripheral surface of the fitting connection hole 18 of the magnetic cylindrical body 4 is attached to the annular first seal groove 14 on the outer periphery of the first fitting portion 11. By sealing the joint hole 18, it is possible to reliably prevent leakage of gas fuel from between the magnetic cylindrical body 4 and the valve seat member 3.

  Further, the annular second seal member 17 on the outer periphery of the second fitting portion 12 is formed on the inner peripheral surface of the attachment hole 1 when the second fitting portion 12 is fitted into the attachment hole 1 of the intake passage member P1 of the engine. Since the close second seal member 17 is mounted, the mounting hole 1 can be sealed to reliably prevent leakage of gas fuel from between the intake passage member P1 and the injection valve I. In addition, the second seal groove 15 for mounting the second seal member 17 is formed in the second fitting portion 12 of the valve seat member 3 itself supported by the magnetic cylindrical body 4 and protruding forward. A special ring for defining the seal groove 15 is not required, which can reduce the number of parts and the number of assembling steps, thereby reducing the cost.

  The present invention is not limited to the above embodiment, and various design changes can be made without departing from the scope of the invention. For example, the number and size of the first to third notches 51 to 53, 53 ′ are arbitrarily set in consideration of the magnetic flux transfer area. The present invention is also applicable to an electromagnetic fuel injection valve for liquid fuel such as gasoline.

The longitudinal cross-sectional view of the electromagnetic fuel injection valve which concerns on the Example of this invention. FIG. 2 is an enlarged view of part 2 of FIG. 1. FIG. 3 is an enlarged sectional view taken along line 3-3 in FIG. 1. FIG. 4 is an enlarged sectional view taken along line 4-4 of FIG. The disassembled perspective view of the coil housing and yoke of the said electromagnetic fuel injection valve.

Explanation of symbols

I ... Electromagnetic fuel injection valve 2 ... Valve housing 3 ... Valve seat member 4 ... Magnetic cylinder 6 ... Fixed core 8 ... · Valve seat 25 ··· magnetic plunger 33 ··· coil 34 ··· coil housing 34a · · · inward flange 35 · · · yoke 45 · · · resin mold layer 51 · · · 1 notch 52 ... second notch 53 ... third notch

Claims (2)

The valve housing (2) includes a valve seat member (3) having a valve seat (8), a magnetic cylinder (4) connecting the front end to the valve seat member (3), and the magnetic cylinder (4). A non-magnetic collar (5) connected to the rear end of the non-magnetic collar (5) and a fixed core (6) connected to the rear end of the non-magnetic collar (5). The magnetic plunger (25) spring-biased in the seating direction with the valve seat (8) is slidably fitted, and the magnetic plunger (25) is opposed to the suction surface at the front end of the fixed core (6). A magnetic body having an inward flange (34a) press-fitted to the outer peripheral surface of the magnetic cylindrical body (4) at the front end of the fixed core (6). The coil housing (34) covers the outer periphery of the coil (33), and the rear end of the coil housing (34) An annular yoke (35) fitted to the peripheral surface is press-fitted to the outer peripheral surface of the fixed core (6), and the outer surface of the valve housing (2) covers the coil housing (34) and the yoke (35). In the electromagnetic fuel injection valve formed with a resin mold layer (45) that fills the internal space of the coil housing (34),
On the inner peripheral surface of the inward flange (34a) and the inner peripheral surface of the yoke (35), the inward flange (34a), the magnetic cylinder (4), the yoke (35), and the fixed core (6) are provided. An electromagnetic fuel characterized in that a plurality of first and second notches (51, 52) are provided at equal intervals in the circumferential direction, which relieve the press-fitting bonding force therebetween and are filled with the resin mold layer (45). Injection valve. The electromagnetic fuel injection valve according to claim 1,
The yoke (35) is press-fitted and coupled to the inner peripheral surface of the coil housing (34), and the press-fitting coupling force between the yoke (35) and the coil housing (34) is eased on the outer peripheral surface of the yoke (35). An electromagnetic fuel injection valve characterized in that a plurality of third notches (53, 53 ') filled with the resin mold layer (45) are provided at equal intervals in the circumferential direction.

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