JP6344940B2 - Electromagnetic fuel injection valve - Google Patents

Description

The present invention relates to an electromagnetic fuel injection valve mainly used for a fuel supply system of an internal combustion engine, and in particular, a valve seat member, a magnetic cylindrical body, a nonmagnetic cylindrical body, and a fixed core are successively connected from the front end to the rear end. A valve housing in which the inside becomes a fuel flow path, a coil assembly including a bobbin and a coil disposed on the outer periphery of the fixed core and the nonmagnetic cylindrical body, and covering the coil assembly, the coil When energizing the assembly, a yoke that forms a magnetic circuit between the fixed core and the magnetic cylindrical body, a valve body that cooperates with the valve seat member, and a valve body that is connected to the valve body and is fitted in the magnetic cylindrical body When the magnetic circuit is formed, the movable core that is attracted to the fixed core to open the valve body, and the coil assembly and the yoke are embedded, and the coil assembly protrudes to one side. mold to form a coupler Be provided with a coating layer made form synthetic resin, the bobbin is a terminal supporting arm for supporting the base of the power supply terminal held by the coupler with connected to the coil have is protruded from one end, the The terminal support arm is embedded in the coating layer together with the bobbin, and the yoke is configured to face the outer peripheral surface of the coil assembly and the outer periphery of the valve housing while facing the front and rear end surfaces of the coil assembly. have possess a front wall and a rear wall portion is secured to the surface, the yoke before sticking to the valve housing, from its side to said coil assembly fitted in the outer periphery of the valve housing The present invention relates to an electromagnetic fuel injection valve that can be fitted .

  Such an electromagnetic fuel injection valve is already known as disclosed in Patent Document 1 below.

JP-A-2005-341786

In Such an electromagnetic fuel injection valve, sticking during its assembly, the yoke, with which the covering coil assembly, the yoke is positioned so as not to rotate around the coil assembly, thereafter, the yoke in the valve housing However, in Patent Document 1, in order to position the yoke so as not to rotate around the coil assembly, a half of the yoke is formed on a terminal support arm that is integrally formed with the yoke and supports the base of the power supply terminal. A disc-shaped rear end wall portion is brought into contact. However, in such a case, prior to fixing the yoke to the valve housing, when positioning the rear end wall portion of the yoke in contact with the terminal support arm using a jig, the rear end wall portion is excessively applied to the terminal support arm. In this case, the terminal support arm may be deformed together with the power supply terminal to cause disconnection of the coil.

  The present invention has been made in view of such circumstances, and enables the yoke to be positioned on the bobbin without applying a load to the terminal support arm prior to fixing the yoke to the valve housing. An object is to provide an electromagnetic fuel injection valve.

In order to achieve the above object, a valve seat member, a magnetic cylindrical body, a nonmagnetic cylindrical body, and a fixed core are successively connected from the front end toward the rear end, and the inside is a fuel flow path, and the fixed core And a coil assembly comprising a bobbin and a coil disposed on the outer periphery of the non-magnetic cylinder, and covering the coil assembly, and energizing the coil assembly, between the fixed core and the magnetic cylinder A yoke that forms a magnetic circuit, a valve body that cooperates with the valve seat member, and is connected to the valve body and fitted in the magnetic cylindrical body, and is attracted to the fixed core when the magnetic circuit is formed. A movable core that opens the valve body, and a synthetic resin coating layer molded so as to form a coupler that protrudes to one side of the coil assembly while embedding the coil assembly and the yoke; Comprising the bobbin The have a terminal support arms for supporting the base of the power supply terminal held by the coupler is protruded from one end with connected to the coil, the terminal support arms are embedded in the coating layer together with the bobbin, and The yoke includes a side wall portion having an arcuate cross section that covers the outer peripheral surface of the coil assembly , and is bent radially inward from both front and rear ends of the side wall portion while facing the front and rear end surfaces of the coil assembly. have possess a front wall and a rear wall portion is secured to the outer peripheral surface of the valve housing, the yoke before sticking to the valve housing, the coil assembly is fitted to the outer periphery of the valve housing the electromagnetic fuel injection valve can be fitted from the side, at least one of the front surface and the rear end face of the bobbin, the pre-fixing to and the valve housing in front embedding into the coating layer Before york The front wall or the rear wall portion engageable with the positioning projections so as to prevent rotation about the coil assembly, and formed apart from said terminal support arms in the circumferential direction of the valve housing, said When the yoke is fitted to the coil assembly from the outer side opposite to the terminal support arm, the positioning protrusions are paired so as to face both ends in the circumferential direction of the front end wall portion or the rear end wall portion. to be placed shall be the feature.

According to the present invention , in the assembly process of the electromagnetic fuel injection valve, when the yoke is fitted to the coil assembly after the coil assembly is fitted to the outer periphery of the valve housing, the yoke is attached to the rear end surface or the front end of the bobbin. By engaging with the positioning protrusions protruding from the surface, positioning of the yoke around the coil assembly before embedding in the coating layer and before fixing to the valve housing can be performed to prevent the yoke from rotating. it can. Then, while holding the jig (not shown) the relationship between such coil assembly and a yoke, but is to fixed by welding or the like yoke on each outer circumferential surface of the magnetic cylindrical body and the fixed core, the positioning projection Since the yoke is pressed against the positioning protrusion by a jig, the load is applied to the coating layer because the terminal support arm that supports the power supply terminal is spaced from the terminal support arm in the circumferential direction . Is not transmitted to the terminal support arm before embedding , and disconnection of the connection portion between the power supply terminal and the coil can be prevented.

Also, when the coating layer and coupler are molded after the yoke is fixed to the valve housing, the yoke engages with the positioning protrusion of the bobbin even if a relative rotational force acts between the yoke and the bobbin due to the flow of the molten resin. Thus, the relative rotation of the yoke and the bobbin can be prevented, and the bobbin and the yoke can be held in a predetermined positional relationship. At that time, the relative rotational force between the bobbin and the yoke is not transmitted to the terminal support arm, and disconnection of the connection portion between the power supply terminal and the coil can be prevented.

Further, in particular, a pair of positioning protrusions are arranged so as to face both ends in the circumferential direction of the front end wall portion or the rear end wall portion of the yoke when the yoke is fitted to the coil assembly from the outer side opposite to the terminal support arm. Runode, while achieving structural simplification of the yoke, along with the positioning of the yoke around the coil assembly can be reliably performed, it is possible to sufficiently separate the two positioning projections from the terminal support arms.

The longitudinal cross-sectional view of the electromagnetic fuel injection valve which concerns on embodiment of this invention. The assembly point explanatory drawing of an electromagnetic fuel injection valve. FIG. 3 is a view taken in the direction of arrow 3 in FIG. 2. The perspective view of a yoke.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In the electromagnetic fuel injection valve of the present invention, the fuel injection side is referred to as the front, and the fuel inlet side is referred to as the rear.

  In FIG. 1, a valve housing 2 of an electromagnetic fuel injection valve I for an engine includes a cylindrical valve seat member 3 and a magnetic cylinder that is fitted to a rear end portion of the valve seat member 3 and is liquid-tightly welded. A body 4, a nonmagnetic cylindrical body 6 that is liquid-tightly welded against the rear end of the magnetic cylindrical body 4, and a front end portion is fitted to the inner peripheral surface of the nonmagnetic cylindrical body 6 to be liquid-tight. A cylindrical fixed core 5 to be welded and a fuel inlet tube 26 fitted to the outer periphery of the rear end of the fixed core 5 and welded.

  The valve seat member 3 includes a valve hole 7 that opens to a front end surface thereof, a conical valve seat 8 that is continuous with the inner end of the valve hole 7, and a cylindrical guide hole 9 that is continuous with a large diameter portion of the valve seat 8. And. A steel plate injector plate 10 having a plurality of fuel injection holes 11 communicating with the valve hole 7 is welded to the front end face of the valve seat member 3 in a liquid-tight manner.

  A portion that does not fit with the fixed core 5 remains at the front end portion of the nonmagnetic cylindrical body 6, and the valve assembly V is accommodated in the valve housing 2 that extends from the portion to the valve seat member 3.

  The valve assembly V includes a spherical valve body 14 that can slide in the guide hole 9 so as to open and close the valve hole 7 in cooperation with the valve seat 8, and a flange portion that is coupled to the valve body 14 by welding. The movable core 12 is slidably fitted on the inner peripheral surface of the magnetic cylindrical body 4 and is opposed to the fixed core 5. A plurality of flat surfaces that allow the passage of fuel are formed around the spherical valve body 14.

  The valve assembly V is provided with a vertical hole 19 that extends from the rear end of the movable core 12 to the front end of the flange 13, and a horizontal hole 20 that opens the vertical hole 19 to the outer peripheral surface of the flange 13. An annular spring seat 24 protruding from the inner peripheral surface of the vertical hole 19 is formed in the middle of the vertical hole 19.

  The fixed core 5 has a vertical hole 21 that communicates with the hollow portion of the fuel inlet cylinder 26, and the vertical hole 21 communicates with the vertical hole 19 of the movable core 12.

  A pipe-shaped retainer 23 is press-fitted into the vertical hole 21 of the fixed core 5, and a valve that urges the movable core 12 toward the valve closing side of the valve body 14 between the retainer 23 and the spring seat 24. The spring 22 is contracted. At that time, the set load of the valve spring 22 is adjusted by the fitting depth of the retainer 23 into the vertical hole 21.

  A ring-shaped stopper member 37 made of a non-magnetic material that slightly protrudes from the rear end surface facing the fixed core 5 is embedded in the movable core 12. The stopper member 37 has a predetermined gap between the opposed end surfaces of the fixed core 5 and the movable core 12 by contacting the front end surface of the fixed core 5 when the fixed and movable cores 5 and 12 are attracted to each other. It will be left.

  A coil assembly 28 is fitted to the outer periphery of the valve housing 2 so as to correspond to the fixed core 5 and the movable core 12. The coil assembly 28 includes a synthetic resin bobbin 29 that fits to the outer peripheral surface of the magnetic cylindrical body 4 from the rear end portion to the fixed core 5, and a coil 30 wound around the synthetic resin bobbin 29. A terminal support arm 29a is integrally formed at the rear end portion of the bobbin 29 to support the base end portion of the power supply terminal 33 protruding to one side, and the terminal of the coil 30 is connected to the power supply terminal 33. .

  The coil assembly 28 is covered with a yoke 31 on a substantially half circumferential surface thereof. The yoke 31 is formed by press-molding a magnetic steel plate. As shown in FIGS. 2 to 4, the yoke 31 has a semicylindrical side wall portion 44 that covers the half circumferential surface of the coil assembly 28, and both ends of the side wall portion 44. From the front end wall portion 45 and the rear end wall portion 46, which are bent inwardly in the radius and face the front and rear end faces of the bobbin 29, and extend forward from the inner end of the front end wall portion 45 to the magnetic cylinder. A semi-cylindrical front boss portion 47 fitted to the outer peripheral surface of the rim 4, and a semi-cylindrical rear boss portion extending rearward from the inner end of the rear end wall portion 46 and fitted to the outer peripheral surface of the fixed core 5 48.

  Corresponding to the outer peripheral surfaces of the magnetic cylindrical body 4 and the fixed core 5 having the same diameter, the inner peripheral surfaces of the front boss portion 47 and the rear boss portion 48 are formed to have the same diameter. Thus, the front half and the rear half of the yoke 31 are formed symmetrically with each other. Therefore, the front end wall portion 45 and the rear end wall portion 46 are compatible, and it is not necessary to define the assembly direction of the yoke 31.

  Thin portions 47a and 48a are formed at the front ends of the front boss portion 47 and the rear boss portion 48, and the portions of the yoke 31 are formed to have the same thickness except for the thin portions 47a and 48a. Thus, in the yoke 31, the magnetic circuit portion between the front boss portion 47 and the rear boss portion 48 is formed with the same thickness. Thereby, both the weight reduction and magnetic efficiency of the yoke 31 can be satisfied.

  Thus, when the yoke 31 is fitted to the coil assembly 28 from the outer side opposite to the terminal support arm 29 a of the bobbin 29, the front boss portion 47 is placed on the outer peripheral surface of the magnetic cylindrical body 4 and the rear boss portion 48. Are fitted to the outer peripheral surface of the fixed core 5. In order to position the yoke 31 around the coil assembly 28, a pair of positioning projections 40 are formed on the front end surface of the bobbin 29 so as to be separated from the terminal support arm 29a. These positioning protrusions 40 are in contact with both ends in the circumferential direction of the semi-disc-shaped front end wall 45 of the yoke 31, thereby preventing the yoke 31 from rotating around the coil assembly 28. A minute gap is provided between the positioning protrusion 40 and both ends in the circumferential direction of the front end wall portion 45, and the front boss portion 47 and the magnetic cylindrical body 4, and the rear boss portion 48 and the fixed core 5 are fitted to each other. It does not interfere.

  The thin portions 47a and 48a of the front boss portion 47 and the rear boss portion 48 are fixed to the outer peripheral surfaces of the magnetic cylindrical body 4 and the fixed core 5 by laser welding (see FIG. 1).

  In FIG. 1 again, a synthetic resin coating layer 27 for embedding them is molded in a portion excluding the coil assembly 28, the fixed core 5, and the rear end portion of the fuel inlet cylinder 26. At this time, a coupler 34 that accommodates and holds the power supply terminal 33 and projects to one side of the coil assembly 28 is formed integrally with the coating layer 27.

  An O-ring 51 is mounted on the outer peripheral surface of the fuel inlet tube 26 between the rear end surface of the coating layer 27 and the flange 26 a at the rear end of the fuel inlet tube 26. A seal member 52 that is in close contact with the front end surface of the coating layer 27 is attached to the outer periphery of the magnetic cylindrical body 4. A fuel filter 43 is attached to the inlet of the fuel inlet cylinder 26.

  Next, the operation of this embodiment will be described.

  The fuel pumped from the fuel pump (not shown) to the fuel inlet cylinder 26 is filtered by the fuel filter 43 and fills the inside of the valve housing 2. When the coil 30 is demagnetized, the valve assembly V is pressed forward by the urging force of the valve spring 22, and the valve body 14 is seated on the valve seat 8. When the coil 30 is energized by energization, the magnetic flux generated by the coil 30 sequentially travels through the yoke 31, the magnetic cylindrical body 4, the movable core 12, and the fixed core 5, and the movable core 12 is moved by the attractive force generated by the magnetic force generated between both the cores 5 and 12. The valve core 14 is attracted to the fixed core 5 against the set load of the valve spring 22 and the valve body 14 is separated from the valve seat 8, so that the valve hole 7 is opened, and the high-pressure fuel in the valve seat member 3 passes through the valve hole 7. Then, the fuel is injected from the fuel injection hole 11 of the injector plate 10 into an intake passage of a throttle body or an engine (not shown) equipped with the electromagnetic fuel injection valve I.

  In the assembly process of the electromagnetic fuel injection valve I, as shown in FIGS. 2 and 3, after the coil assembly 28 is fitted on the outer periphery of the valve housing 2, the yoke 31 is attached to the coil assembly 28, and the bobbin 29. The front boss portion 47 is fitted to the outer peripheral surface of the magnetic cylindrical body 4 and the rear boss portion 48 is fitted to the outer peripheral surface of the fixed core 5 by fitting from the outside opposite to the terminal support arm 29a. At this time, both end portions in the circumferential direction of the semi-disc-shaped front end wall portion 45 of the yoke 31 are brought into contact with a pair of positioning projections 40 protruding from the rear end surface of the bobbin 29, thereby the coil assembly 28 of the yoke 31. Positioning around is performed to prevent the yoke 31 from rotating.

  In a state where the relationship between the coil assembly 28 and the yoke 31 is held by a jig (not shown), the thin-walled portions 47a and 48a of the front boss portion 47 and the rear boss portion 48 of the yoke 31 are connected to the magnetic cylindrical body 4 and the fixed core. 5 is laser welded to each outer peripheral surface. According to the laser welding of such thin portions 47a and 48a, the yoke 31 can be welded to the valve housing 2 with relatively little heat input.

  By the way, since the positioning projection 40 is disposed away from the terminal support arm 29a that supports the power supply terminal 33, the front end wall portion 45 of the yoke 31 may be pressed against the positioning projection 40 by a jig. The load is not transmitted to the terminal support arm 29a, and disconnection of the connection portion between the power supply terminal 33 and the coil 30 can be prevented.

  In particular, the yoke 31 is bent inward in the radial direction from both ends of the side wall portion 44 so as to face the front and rear end surfaces of the bobbin 29 while covering the half circumferential surface of the coil assembly 28. The front end wall 45 and the rear end wall 46 are fixed to the outer peripheral surface of the valve housing 2, and the positioning projection 40 has a yoke 31 on the outer side opposite to the terminal support arm 29 a. When the coil assembly 28 is fitted to the coil assembly 28 from the side, the pair of the front end wall portions 45 are arranged so as to face both ends in the circumferential direction, thereby simplifying the structure of the yoke 31 and The yoke 31 can be reliably positioned, and the positioning protrusion 40 can be sufficiently separated from the terminal support arm 29a.

  After the yoke 31 is welded to the valve housing 2, the coating layer 27 for embedding the coil assembly 28 and the like and the coupler 34 for holding the power supply terminal 33 are molded. At that time, even if a relative rotational force acts between the yoke 31 and the bobbin 29 due to the flow of the molten resin, the circumferential end of the semi-disc-shaped front end wall 45 of the yoke 31 is positioned on the rear end surface of the bobbin 29. By abutting against the protrusion 40, relative rotation of the yoke 31 and the bobbin 29 can be prevented, and the bobbin 29 and the yoke 31 can be held in a predetermined positional relationship. At this time, the relative rotational force between the bobbin 29 and the yoke 31 is not transmitted to the terminal support arm 29a, and disconnection of the connection portion between the power supply terminal 33 and the coil 30 can be prevented.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to it, A various design change is possible in the range which does not deviate from the summary. For example, the positioning protrusions 40 can be provided on the rear end surface of the bobbin 29, or can be provided on both front and rear end surfaces.

I ... Electromagnetic fuel injection valve 2 ... Valve housing 3 ... Valve seat member 4 ... Magnetic cylinder 5 ... Fixed core 6 ...・ Non-magnetic cylindrical body 12... Movable core 14... Valve body 27 ..covering layer 28... Coil assembly 29. · Yoke 33 ··· Feeding terminal 34 ··· Coupler 40 ··· Positioning protrusion 44 ··· Side wall portion 45 ··· Front end wall portion 46 ··· Rear end wall portion

Claims (1)

A valve housing (3), a magnetic cylindrical body (4), a non-magnetic cylindrical body (6), and a fixed core (5) are successively connected from the front end to the rear end, and the inside is a fuel flow path ( 2), a coil assembly (28) comprising a bobbin (29) and a coil (30) disposed on the outer periphery of the fixed core (5) and the nonmagnetic cylindrical body (6), and the coil A yoke (31) that covers the assembly (28) and forms a magnetic circuit between the fixed core (5) and the magnetic cylindrical body (4) when the coil assembly (28) is energized, and the valve seat member ( 3) and a valve body (14) that cooperates with the valve body (14), and is fitted into the magnetic cylindrical body (4). When the magnetic circuit is formed, the fixed core (5) The movable core (12) that is sucked to open the valve body (14), the coil assembly (28), and the yaw While embedded (31), becomes and a said coil assembly (28) molded synthetic resin coating layer to form a coupler (34) projecting on one side of (27),
The bobbin (29) has a terminal support arm (29a) that is connected to the coil (30) and supports the base of the power supply terminal (33) held by the coupler (34), protruding from one end thereof. A terminal support arm (29a) is embedded in the coating layer (27) together with the bobbin (29), and the yoke (31) has an arcuate cross section covering the outer peripheral surface of the coil assembly (28). And the outer peripheral surface of the valve housing (2) while being bent radially inward from both front and rear ends of the side wall portion (44) and facing the front and rear end surfaces of the coil assembly (28). front end wall portion which is fixed (45) and the rear wall section (46) have been closed, the said yoke (31) before sticking to the valve housing (2), said valve housing (2) The coil assembly (28) fitted on the outer periphery is on that side The electromagnetic fuel injection valve can be fitted from
At least one of the front surface and the rear end face of the bobbin (29), said covering layer (27) within and in front embedding into the valve the yoke before fixing to the housing (2) (31), wherein A positioning projection (40) engageable with the front end wall (45) or the rear end wall (46) to prevent rotation about the coil assembly (28) is provided on the valve housing (2). Forming away from the terminal support arm (29a) in the circumferential direction ;
When the positioning protrusion (40) is engaged with the coil assembly (28) from the outer side opposite to the terminal support arm (29a), the front end wall (45) or the positioning protrusion (40) A pair of electromagnetic fuel injection valves arranged so as to face both ends in the circumferential direction of the rear end wall (46) .

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