JP2008057430A - Solenoid operated fuel injection valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent operation noise by increasing stiffness around a valve seat member with a simple structure and suppressing vibration of the valve seat member caused by collision between a valve seat and a valve element. <P>SOLUTION: In a solenoid operated fuel injection valve having a magnetic cylinder 4 and a fixed core 5 magnetically connected via a magnetic coil housing 31 for storing a coil assembly 28, covering the coil housing 31 and at least part of a valve housing 31 by hard synthetic resin coating body 32, having a coupler 34 formed on the coating body 32 as one unit, and having an annular seal groove 43 retaining a seal member 41 formed on a front end outer circumference of the valve housing 31, a metal cap 42 surrounding a front end of the valve seat member 3 is pressed and fixed on an outer circumference surface of the valve housing 31, and a front end wall of the seal groove 43 is composed of the cap 42. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel injection valve mainly used for a fuel supply system of an internal combustion engine, and in particular, a valve seat member having a valve seat at a front end portion, and a magnetic cylinder coupled coaxially to a rear end of the valve seat member. A non-magnetic collar coaxially coupled to the rear end of the magnetic cylinder and a fixed core fitted and fixed to the rear of the non-magnetic collar, and the valve housing includes the valve seat A valve assembly comprising a valve body that can be seated on the movable body, a movable core that is connected to a rear end of the valve body and faces a front end suction surface of the fixed core, and a seating direction of the valve body on the valve seat A valve spring for energizing the valve assembly, a coil assembly disposed so as to surround the nonmagnetic collar and the fixed core, and a magnetic coil housing for accommodating the coil assembly through the magnetic coil housing. The magnetic cylinder and the fixed core are magnetically connected, and this coil is A housing and at least a part of the valve housing are covered with a hard synthetic resin covering, and a coupler for supporting a terminal connected to the coil assembly is integrally formed on the covering, so that a front end portion of the valve housing is formed. The present invention relates to an improvement in an electromagnetic fuel injection valve in which an annular seal groove for holding a seal member is formed on the outer periphery.

Such an electromagnetic fuel injection valve is already known as disclosed in Patent Document 1 below.
JP 2005-240731 A

  In recent years, in order to meet the demands for improving the output of internal combustion engines, such electromagnetic fuel injection valves have to satisfy both large fuel flow characteristics and high responsiveness at the same time. It is necessary to increase the diameter, increase the suction force between the fixed core and the movable core, and increase the set load of the valve spring.

  However, an electromagnetic fuel injection valve that satisfies these conditions has a new problem of increased operating noise. Especially when the valve body is closed, noise caused by the collision between the valve seat and the valve body is generated. Get out big. In a conventional electromagnetic fuel injection valve, a coupler is integrally formed on a cover made of a synthetic resin that covers a coil housing and at least a part of the valve housing. In order to improve vibration resistance, glass fiber or other reinforcing fibers are mixed. However, the coated body with a coupler thus strengthened is hard, and is caused by collision between the valve seat and the valve body. When the vibration is transmitted to the covering through the coil housing or the fixed core, the covering may emit a resonance sound.

  The present invention has been made in view of such circumstances, strengthening the rigidity around the valve seat member with a simple structure, and suppressing the vibration of the valve seat member due to the collision between the valve seat and the valve body, It is another object of the present invention to provide the electromagnetic fuel injection valve that suppresses the generation of resonance noise of the coated body made of a hard synthetic resin with a coupler, effectively reduces operating noise, and has high quietness.

  In order to achieve the above object, the present invention provides a valve seat member having a valve seat at a front end, a magnetic cylinder coupled coaxially to the rear end of the valve seat member, and a rear end of the magnetic cylinder. A non-magnetic collar coupled coaxially and a fixed core fitted and fixed to the rear part of the non-magnetic collar constitute a valve housing. In the valve housing, a valve body seatable on the valve seat and the valve A valve assembly comprising a movable core connected to the rear end of the body and facing the front end suction surface of the fixed core, and a valve spring for biasing the valve assembly in the seating direction of the valve body on the valve seat A coil assembly is disposed so as to surround the non-magnetic collar and the fixed core, and the magnetic cylinder and the fixed core are magnetically connected via a magnetic coil housing that houses the coil assembly. The coil housing and a small amount of the valve housing. Both of them are covered with a cover made of hard synthetic resin, and a coupler that supports the terminal connected to the coil assembly is formed integrally with the cover, and a seal member is held on the outer periphery of the front end of the valve housing. In the electromagnetic fuel injection valve in which an annular seal groove is formed, a metal cap that surrounds the front end portion of the valve seat member is press-fitted and fixed to the outer peripheral surface of the valve housing, and the cap is used to seal the seal groove. The first feature is that the front end wall is configured.

  In addition to the first feature, the present invention has a second feature in that the covering is formed of a hard synthetic resin mixed with granular rubber.

  According to the first feature of the present invention, since the metal cap surrounding the front end of the valve seat member is press-fitted and fixed to the outer peripheral surface of the valve housing, the cap effectively enhances the rigidity of the valve seat member. Therefore, the vibration of the valve seat member due to the impact when the valve body is seated on the valve seat can be effectively suppressed, and the radiated sound accompanying the impact from the valve seat member can also be suppressed. It can be shut off by the cap and can contribute to the improvement of the quietness of the electromagnetic fuel injection valve. In addition, since the cap also serves as the front end wall of the seal groove that holds the seal member, the cap can contribute to a reduction in the number of parts of the electromagnetic fuel injection valve and a reduction in cost.

  According to the second aspect of the present invention, even if the impact is transmitted from the coil housing or the fixed core to the hard synthetic resin covering integrally provided with the coupler, the granular rubber mixed in the covering is provided. By absorbing the vibration, it is possible to prevent the generation of resonance noise of the cover, which can contribute to further improvement in the quietness of the electromagnetic fuel injection valve.

  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 a first embodiment of the present invention, FIG. 2 is an enlarged view of a part 2 of FIG. 1, and FIG. 3 is a second embodiment of the present invention. FIG. 4 is a diagram for comparing operation noise between the electromagnetic fuel injection valve of the present invention and the conventional one.

  First, in FIG. 1, the valve housing 2 of the fuel injection valve I includes a cylindrical valve seat member 3 having a valve seat 8 at a front end portion, and a coaxial liquid-tight outer periphery of the valve seat member 3. The magnetic cylinder 4 to be fitted and fixed, the nonmagnetic collar 6 coaxially and liquid-tightly joined to the rear end of the magnetic cylinder 4, and coaxial to the inner peripheral surface of the rear end of the nonmagnetic collar 6 The fixed core 5 is fitted and fixed in a liquid-tight manner, and the fuel inlet cylinder 26 is provided coaxially and continuously at the rear end of the fixed core 5.

  The valve seat member 3 is provided with a valve hole 7 penetrating the center of the conical valve seat 8 and a cylindrical guide hole 9 connected to the rear end of the valve seat 8.

  A portion that does not fit with the fixed core 5 remains at the front end portion of the nonmagnetic collar 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 valve body 18 including a spherical valve portion 16 that is slidably fitted in the guide hole 9 and opens / closes with respect to the valve seat 8 and a hollow flange portion 17 that supports the spherical valve portion 16; The movable core 12 is welded to the flange portion 17 and faces the front end suction surface of the fixed core 5, and the movable core 12 is slidably guided from the inner peripheral surface of the nonmagnetic collar 6, The inner peripheral surface of the body 4 is prevented from contacting as much as possible.

  As shown in FIGS. 1 and 2, the valve assembly V includes a vertical hole 19 that ends from the rear end surface of the movable core 12 and before the valve portion 16, and the vertical hole 19 communicates with the outer peripheral surface of the flange portion 17. And a plurality of chamfered portions 16 a formed on the outer peripheral surface of the valve portion 16 and connected to the lateral hole 20. In the middle of the vertical hole 19, an annular spring seat 24 composed of an end wall of the flange portion 17 is formed.

  The fixed core 5 has a vertical hole 21 communicating with the vertical hole 19 of the valve assembly V at the center, and a pipe-like retainer 23 (see FIG. 1) that is press-fitted into and fixed to the vertical hole 21. The valve spring 22 is contracted between the spring seat 24 and the valve assembly V is biased in the seating direction of the valve portion 16 with the valve seat 8. A highly hard and cylindrical stopper member 14 is fixed to the inner peripheral surface of the movable core 12 so as to surround the valve spring 22. The stopper member 14 has its outer end slightly protruded from the rear end suction surface of the movable core 12, and usually the front end suction of the fixed core 5 with a gap corresponding to the valve opening stroke of the valve assembly V. Faced with the face.

  1 and 2, a coil assembly 28 is fitted on the outer periphery of the valve housing 2. The coil assembly 28 includes a bobbin 29 that fits on the outer peripheral surface from the rear end portion of the magnetic cylinder 4 to the nonmagnetic collar 6 and the fixed core 5, and a coil 30 wound around the bobbin 29. The magnetic cylindrical body 4 and the fixed core 5 are magnetically connected by a magnetic coil housing 31 that houses the coil assembly 28.

  As shown in FIG. 2, the magnetic cylinder 4 is formed with an annular positioning step between the intermediate cylinder 4m and the front end of the intermediate cylinder 4m and between the outer peripheral surface of the intermediate cylinder 4m. It consists of a thick-walled front cylinder part 4f and a thick-walled rear cylinder part 4r that is connected to the rear end of the intermediate cylinder part 4m and forms an annular step 39 between the inner peripheral surface of the intermediate cylinder part 4m. Yes.

  Thus, the valve seat member 3 is press-fitted and fixed to the inner peripheral surfaces of the front cylinder portion 4f and the intermediate cylinder portion 4m, and the valve seat member 3 is opposed so that the rear end thereof does not contact the annular step portion 39. Be placed. In this way, the diameter of the valve body 18 can be increased by making the valve seat member 3 larger in diameter than the movable core 12.

  The movable core 12 is slidably accommodated in the rear cylinder part 4r, the front end face of the nonmagnetic collar 6 is welded to the inner peripheral side of the rear end face of the rear cylinder part 4r, and the outer peripheral side of the rear end face is An annular positioning step 38 that supports the front end of the bobbin 29 and restricts its axial position is formed.

  On the other hand, the coil housing 31 includes a body portion 31a that surrounds the coil assembly 28, a front end wall portion 31b that faces radially inward from the front end of the body portion 31a and faces the front end of the bobbin 29, and the front end The boss part 31c protruding forward from the inner peripheral part of the wall part 31b is integrally formed of a magnetic material. In particular, the axial thickness t1 of the front end wall part 31b is the radial thickness of the body part 31a. It is formed to be larger than t2. The boss portion 31c is formed such that its radial thickness is smaller than the radial thickness t2 of the body portion 31a. As a result, a forward annular step 40 is formed between the boss portion 31c and the front end wall portion 31b. .

  Thus, the front end wall part 31b and the boss part 31c are press-fitted and fixed to the outer peripheral surfaces of the intermediate cylinder part 4m and the rear cylinder part 4r of the magnetic cylinder 4, and as a result, the rear cylinder part 4r and the front end wall part 31b , A magnetic path forming portion 36 that surrounds the movable core 12 over substantially the entire inner peripheral surface and magnetically connects the movable core 12 and the body portion 31a is formed. The magnetic path forming portion 36 has an axial thickness t1. Is larger than the radial thickness t2 of the body portion 31a, like the front end wall portion 31b. Thus, a large magnetic path area is imparted to the magnetic path forming portion 36 so as to prevent magnetic flux saturation at the front end wall portion 31b of the coil housing 31.

  Further, the front end of the boss portion 31c comes into contact with the positioning step portion 37 of the nonmagnetic collar 6 so that the axial position of the coil housing 31 is restricted. At this time, the front end wall portion 31 b faces the front end of the bobbin 29 with a gap g so as not to prevent the bobbin 29 from coming into contact with the positioning step portion 38.

  The front end of the boss portion 31 c that is press-fitted and fixed to the magnetic cylinder 4 extends to an intermediate position in the axial direction of the valve seat member 3. Therefore, the magnetic cylinder 4 and the boss portion 31 c are doubly press-fitted and fixed to the outer peripheral surface of the valve seat member 3, which contributes to strengthening the rigidity of the valve seat member 3. The magnetic cylinder 4 and the coil housing 31 are manufactured by forging, cutting or sintering.

  The rear end portion of the coil housing 31 and the fixed core 5 are magnetically connected to each other by a yoke 35 that is press-fitted and fixed therebetween. The yoke 35 is also formed so that the axial thickness is larger than the radial thickness t2 of the body portion 31a, like the front end wall portion 31b. Further, the yoke 35 is in contact with the rear end of the bobbin 29 and also serves to clamp and fix the bobbin 29 in cooperation with the positioning step portion 38 of the magnetic cylinder 4.

  An injector plate 10 having a plurality of fuel injection holes 11 communicating with the valve hole 7 is joined to the front end surface of the valve seat member 3 in an annular shape by laser welding. A metal cap 42 covering the outer peripheral part of the front surface of the injector plate 10 and the exposed part of the valve seat member 3 from the magnetic cylinder 4 is press-fitted and fixed to the outer peripheral surface of the front cylinder part 4 f of the magnetic cylinder 4. Therefore, the magnetic cylinder 4 and the cap 42 are doubly press-fitted and fixed to the outer peripheral surface of the valve seat member 3, which contributes to strengthening the rigidity of the valve seat member 3.

  The cap 42 is formed with a flange 42a facing the annular step 40 on the outer peripheral side of the boss 31c of the coil housing 31, and an O-ring is formed by the flange 42a, the annular step 40 and the outer periphery of the boss 31c. A seal groove 43 that holds the seal member 41 is defined. When the front end portion of the electromagnetic fuel injection valve I is fitted in the mounting hole 46 provided in the intake system member 45 of the engine, the seal member 41 is in close contact with the inner peripheral surface of the mounting hole 46 and seals the mounting hole 46. To do.

  Referring again to FIG. 1, a fuel inlet cylinder 26 whose inside communicates with the retainer 23 is fitted and liquid-tight welded to the outer peripheral surface of the rear end portion of the fixed core 5, and a fuel inlet cylinder 26 is connected to the inlet of the fuel inlet cylinder 26. A filter 27 is attached.

  A hard synthetic resin covering 32 is formed on the outer peripheral surface of the coil housing 31 from the latter half of the coil housing 31 to the fuel inlet cylinder 26. At that time, the synthetic resin is filled into the coil housing 31 through the slits 31 s formed in a part of the body portion 31 a of the coil housing 31 to embed the coil assembly 28. Further, a coupler 34 protruding in one side is integrally formed in the intermediate portion of the covering body 32, and the coupler 34 holds a power feeding terminal 33 that is continuous with the coil 30.

  The hard synthetic resin is obtained by mixing glass fiber and granular rubber to have a flexural modulus of 9000 MPa or more. An example of the component is given below.

Glass fiber 35%
Granular rubber: 5-7%
Aromatic Nylon Polymer: Remainder Next, the operation of this embodiment will be described.

  When the coil 30 is demagnetized, the valve assembly V is pressed forward by the biasing force of the valve spring 22, and the valve body 18 is seated on the valve seat 8. In this state, the fuel pressure-fed from a fuel pump (not shown) to the fuel inlet cylinder 26 is made to wait in the valve seat member 3 through the pipe-like retainer 23, the vertical holes 19 and the horizontal holes 20 of the valve assembly V.

  When the coil 30 is energized by energization, the magnetic flux F generated thereby is movable from the fixed core 5 through the yoke 35, the body portion 31a of the coil housing 31, the front end wall portion 31b and the magnetic cylinder 4 while bypassing the nonmagnetic collar 6. The movable core 12 is sequentially moved to the core 12 and then to the fixed core 5, and the movable core 12 is attracted to the fixed core 5 against the set load of the valve spring 22 by the magnetic force generated thereby, and the valve body 18 is shown in FIG. 2. Thus, the high-pressure fuel in the valve seat member 3 advances toward the valve hole 7 along the valve seat 8 and is injected while being atomized from the fuel injection hole 11. .

  If the energization of the coil 30 is interrupted after a predetermined time, the movable core 12 is pulled away from the fixed core 5 by the urging force of the valve spring 22, the valve body 18 is seated on the valve seat 8, the valve hole 7 is closed, The fuel injection from the fuel injection hole 11 is stopped.

  By the way, the seating of the valve body 18 on the valve seat 8 is performed shockingly. However, the rigidity of the valve seat member 3 having the valve seat 8 is effectively enhanced by the double press-fitting and fixing of the magnetic cylinder 4 and the cap 42 on the outer peripheral surface thereof. The resulting vibration of the valve seat member 3 can be effectively suppressed. At the same time, the exposed surface from the magnetic cylinder 4 is covered with the cap 42 in the valve seat member 3, so that the radiated sound accompanying the impact from the valve seat member 3 can also be effectively blocked by the cap 42. .

  Further, even if vibration due to the impact is transmitted to the covering body 32 integrally provided with the coupler 34 through the coil housing 31, the fixed core 5, and the fuel inlet cylinder 26, the outer peripheral surfaces thereof are made of glass fibers and granules. Since it is covered with a hard synthetic resin coating 32 having a flexural modulus of 9000 MPa or more by mixing with rubber, particularly the granular rubber dispersed in the coating 32 will absorb the vibration. , The generation of resonance sound of the covering 32 can be effectively suppressed.

  Thus, the quietness of the electromagnetic fuel injection valve I is improved. In addition, the cap 42 has a flange 42a that also serves as the front end wall of the seal groove 43 that holds the seal member 41. This contributes to a reduction in the number of parts of the electromagnetic fuel injection valve I and, in turn, a reduction in cost. Can do.

  The glass fibers dispersed in the covering body 32 increase the strength and vibration resistance of the covering body 32 and contribute to ensuring the durability of the electromagnetic fuel injection valve I.

  Next, a second embodiment of the present invention shown in FIG. 3 will be described.

  In the second embodiment, the metal cap 42 is press-fitted and fixed to the outer peripheral surface of the front end portion of the valve seat member 3 exposed from the magnetic cylinder 4. Since other configurations are the same as those of the previous embodiment, portions corresponding to those of the previous embodiment are denoted by the same reference numerals in FIG.

  Also in the second embodiment, the rigidity of the valve seat member 3 is effectively enhanced by the metal cap 42 press-fitted to the outer peripheral surface of the front end portion. The vibration of the valve seat member 3 due to the impact generated when seated on the seat can be effectively suppressed.

  The electromagnetic fuel injection valve I according to the present invention in which the mounting conditions of the cap 42 are the same and granular rubber is mixed in the covering 32, and the electromagnetic fuel injection valve in which the covering 32 does not contain granular rubber (comparative example). As a result of the noise comparison test, the results shown in FIG. 4 were obtained. That is, in the electromagnetic fuel injection valve I of the present invention, the sound pressure indicating noise can be reduced to about half of the comparative example. From this, it can be seen that the granular rubber mixed in the synthetic resin of the covering 32 is effective in increasing the sound absorption of the covering 32.

  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 cap 42 can be press-fitted and fixed to the outer peripheral surfaces of both the valve seat member 3 and the magnetic cylinder 4 so as to combine the first and second embodiments.

1 is a longitudinal sectional view of an electromagnetic fuel injection valve according to a first embodiment of the present invention. FIG. 2 is an enlarged view of part 2 of FIG. 1. FIG. 3 is a view corresponding to FIG. 2 showing a second embodiment of the present invention. The operation noise comparison diagram of the electromagnetic fuel injection valve of the present invention and the conventional one.

Explanation of symbols

I ... Electromagnetic fuel injection valve 2 ... Valve housing 3 ... Valve seat member 4 ... Magnetic cylinder 5 ... Fixed core 6 ... · Non-magnetic collar 8 ··· Valve seat 12 ··· movable core 18 ··· valve body 22 ··· valve spring 28 ··· coil assembly 31 · · · coil housing 33 ... Terminal 34 ... Coupler 41 ... Seal member 42 ... Cap 43 ... Seal groove

Claims (2)

A valve seat member (3) having a valve seat (8) at the front end, a magnetic cylinder (4) coaxially coupled to the rear end of the valve seat member (3), and a magnetic cylinder (4) A non-magnetic collar (6) coupled coaxially to the rear end and a fixed core (5) fitted and fixed to the rear part of the non-magnetic collar (6) constitute a valve housing (2). (2) The valve body (18) that can be seated on the valve seat (8), and the movable body that is connected to the rear end of the valve body (18) and faces the front end suction surface of the fixed core (5). A valve assembly (V) comprising a core (12) and a valve spring (22) for urging the valve assembly (V) in the seating direction of the valve body (18) on the valve seat (8). A coil assembly (28) is disposed so as to enclose and surround the non-magnetic collar (6) and the fixed core (5), and a magnetic assembly for accommodating the coil assembly (28). The magnetic cylinder (4) and the fixed core (5) are magnetically connected via a coil housing (31) of the coil housing, and the coil housing (31) and at least a part of the valve housing (31) And a coupler (34) for supporting a terminal (33) connected to the coil assembly (28) is integrally formed on the cover (32). In the electromagnetic fuel injection valve in which an annular seal groove (43) for holding the seal member (41) is formed on the outer periphery of the front end portion of the housing (31),
A metal cap (42) surrounding the front end of the valve seat member (3) is press-fitted and fixed to the outer peripheral surface of the valve housing (31), and the front end of the seal groove (43) is secured by the cap (42). An electromagnetic fuel injection valve characterized by comprising a wall. The electromagnetic fuel injection valve according to claim 1,
An electromagnetic fuel injection valve, wherein the covering (32) is formed of a hard synthetic resin mixed with granular rubber.

Images