JPH0521162U - Injector for internal combustion engine - Google Patents

Abstract

(57) [Summary] [Purpose] An internal fuel engine that is easy to process, has abrasion resistance, has good fuel sheet properties, is resistant to fatigue damage, has good valve operation stability, and has good fuel discharge foam. For injectors. In an electromagnetic fuel injector having a ball valve, a ball valve 9, a valve seat surface 11, and a contact surface 1 of a fixed core
The surface of 9a is subjected to non-magnetic high hardness treatment, the fuel seat projection 13 is provided on the valve seat surface 11, and the return spring 8 is formed in a drum shape. In addition, in front of the valve hole 14, the discharge space 15 and the two-hole plate 1 for discharging the discharged fuel in two directions at optimum positions.
6 is provided.

Description

[Detailed description of the device]

A. Purpose of the Invention (1) Field of Industrial Application This invention relates to an injector, which is an electromagnetic fuel injection valve, which is applied to an internal combustion engine in an automobile or the like.

(2) Conventional Technology As an injector of this type, for example, one disclosed in JP-A-55-10016 or JP-A-58-67968 is known. The structure of this known injector will be described with reference to FIG. 8. Reference numeral 100 is an orifice plate for closing one end of a hole 104 formed in the housing 102, and the orifice 106 formed in the orifice plate 100 is a spherical valve. It can be opened and closed by the body (ball valve) 108. The other end of the hole 104 is closed by a fixed core 110, and the housing 102 and the fixed core 110 are abutted and fixed at stepped portions formed in each. The tip of the fixed core 110 projects to the vicinity of the valve body 108 to regulate the lift of the ball valve 108. A bobbin 114 formed by winding an electromagnetic coil 112 is accommodated in the hole 104. When the electromagnetic coil 112 is excited, the ball valve 108 is absorbed by the fixed core 110 and the orifice 106 is opened. Become.

An injector using such a ball valve has a smaller number of parts than an injector combining a needle valve and a plunger as disclosed in Japanese Utility Model Laid-Open No. 58-90365, for example, and the number of parts is small. Although it has advantages such as a simple shape, in the injector using the conventional ball valve, the ball valve opens and closes in a high cycle and collides, so the ball valve and valve seat wear and fatigue fracture due to repeated stress. Is caused. Therefore, if a ball valve or valve seat made of a hard material is used, it is difficult to process the ball valve or valve seat, and it is also susceptible to impact. In addition, the injector using the conventional ball valve does not have a sufficient fuel seat property for the ball valve, and the ball valve is not sufficiently stable when it is seated on the valve seat. Furthermore, the conventional injector using a ball valve was not sufficient in the form of fuel discharge compared to the injector combining a needle valve and a plunger.

(3) Problems to be Solved by the Invention The present invention has been made in view of the above circumstances, and an object thereof is to solve the problems of the above-mentioned conventional technology and to manufacture the structure with a simple structure. It is intended to provide an injector for an internal combustion engine that can reduce cost.

B. Configuration of the Invention (1) Means for Solving the Problems The injector for an internal combustion engine of the present invention has the following configuration to achieve the above object. That is, a housing 1 having a substantially cylindrical shape; a bobbin 4 housed in the housing 1, having an inner hole 2 penetrating in the axial direction in the central portion, and having an electromagnetic coil 3 wound around it; A fixed core 6 inserted into the inner hole 2 and having an axial hole 5 bored in the axial direction thereof and fixedly held by the housing 1; and a return spring 8 facing the fixed core 6 In a injector for an internal combustion engine having a ball valve 9 made of a magnetic material, the surface of the ball valve 9 is non-magnetic and highly hardened, and the housing 1 has a valve seat surface on which the ball valve 9 is seated. 11 and a valve hole 14, the valve seat surface 11 has a conical surface shape, and has a fuel seat projection 13 for enhancing the fuel seat property of the ball valve 9, and the return spring 8 Has a drum shape And wherein the door.

(2) Action When the electromagnetic coil 3 is demagnetized, the ball valve 9 is pushed back by the return spring 8 to be seated on the valve seat surface 11 and closed, but when the electromagnetic coil 3 is excited, the fixed core 6 Then, the ball valve 9 is sucked and opened, and the pressurized fuel is discharged from the valve hole 14 to the discharge space 15. The discharge space 15 is a space for discharging the discharged fuel in two directions at optimal positions, and the pressurized fuel discharged into the discharge space 15 is atomized and sprayed from the 2-hole plate 16 in two directions. The ball valve 9 reciprocates in a high cycle in response to a signal (pulse current) from the control unit. The ball valve 9 has a non-magnetic and high hardness surface so that it has abrasion resistance, shock and repetitive stress. It is also strong against fatigue damage caused by. Further, since the fuel seat projection 13 is provided on the conical valve seat surface 11, the fuel seat property is good with respect to the reciprocating movement of the ball valve 9. Further, since the return spring 8 has an hourglass shape, the operation stability of the ball valve 9 is improved.

(3) Embodiment An embodiment of the ingenter for an internal combustion engine of the present invention will be described with reference to the drawings. 1 to 6 show an embodiment of an injector for an internal combustion engine of the present invention. That is, FIG. 1 shows the whole structure, and FIGS. 2 to 6 show each partial structure of this injector. In this description, "forward" and "rearward" are defined according to the flow of fuel. That is, the upstream side is “rear” and the downstream side is “front”.

As shown in FIG. 1, the injector I includes a housing 1 having a substantially cylindrical shape; and an inner hole 2 which is housed in the housing 1 and axially penetrates in a central portion thereof. And a synthetic resin bobbin 4 formed by winding an electromagnetic coil 3; a fixed core 6 having a fuel passage 5 inserted into the inner hole 2 and penetrating the axial center thereof; and an intermediate portion of the fixed core 6. A yoke 7 which is provided integrally with the fixed core 6 and which is crimped and fixed by the housing 1 by sandwiching the bobbin 4; and a ball valve made of a magnetic material, which is arranged facing the fixed core 6 via a return spring 8. 9 and; are included. Reference numeral 10 is a ball valve accommodating space for accommodating the ball valve 9 in the moving range. The housing 1, the yoke 7, the fixed core 6 and the ball valve 9 form a magnetic path around the electromagnetic coil 3. That is, the ball valve 9 has a function of a movable core (also called an armature).

Further, the front side of the housing 1 is reduced in diameter, and a cone-shaped valve seat surface 11 on which the ball valve 9 is seated is provided therein, and a nozzle portion 12 extending to the front end is formed. The fuel always fills the valve seat surface 11. On the valve seat surface 11, a fuel seat projection 13 for enhancing the fuel seat property of the ball valve 9 is formed in an annular shape, and a valve hole continuous with the valve seat surface 11 and penetrating into the nozzle portion 12 at the central portion. 14 are drilled.

A discharge space portion 15 for discharging the discharged fuel in two directions at optimal positions is formed inside the nozzle portion 12 in the front portion of the valve hole 14, and a front side end surface of the discharge space portion 15 is formed. The two-hole plate 16 is fixed by caulking the tip of the nozzle portion 12. 16a is a hole for discharging the fuel. Reference numeral 12a is an assist air introduction hole that is opened in a side portion of the nozzle portion 12 so as to communicate with the discharge space portion 15. The assisted air introducing hole 12a is used to miniaturize the discharged fuel. The rear end of the discharge space portion 15 is formed in a conical surface shape, and the valve hole 14 is provided in the center thereof.

A terminal 17 for supplying an electric current to the magnetic coil 3 wound around the bobbin 4 is embedded in the rear portion of the bobbin 4, and penetrates the yoke 7 to be taken out to the outside. The terminal 17 is protected by a resin socket 18.

The fixed core 6 is a long cylindrical body, and is divided into a front portion 6 a and a rear portion 6 b in front of and behind the yoke 7. The rear portion 6 b has its outer diameter expanded and protrudes outside the housing 1. It forms the fuel inlet. The front portion 6a is inserted into the inner hole 2 of the bobbin 4 as described above. Reference numeral 19 denotes a further tip portion of the front portion 6a of the fixed core 6.

A hollow sleeve 20 is pushed and inserted into the middle portion of the fuel passage 5, and a return spring 8 is interposed between the hollow sleeve 20 and the ball valve 9 to push the rear end surface of the ball valve 9 to the front side. The valve 9 is always held in the closed position. A fuel filter 22 having a flange 21 is mounted on the rear end of the fuel passage 5, and the O-ring 23 mounted on the outer periphery of the rear end of the fixed core 6 is prevented from falling by the flange 21.

FIG. 2 shows the front surface of the 2-hole plate 16. As shown in the figure, two holes 16a are provided side by side.

FIG. 3 shows a cross section of the housing 1 taken out independently. As illustrated, on the valve seat surface 11, the ridge portion 13 is formed continuously in an annular shape. In the figure, reference numerals 1a and 1b denote caulking portions formed at the front end portion and the rear end portion of the housing 1 to be thin.

FIG. 4 shows the return spring 8 enlarged. The return spring 8 has an hourglass shape, which improves the operational stability of the ball valve 9.

FIG. 5 shows a cross section of the fixed core 6 taken out independently, and FIG. 6 is a side view of the tip surface of the fixed core 6. As shown in the drawing, the tip end portion 19 of the fixed core 6 is an abutting surface 19a on the inner peripheral side when the ball valve 9 is sucked, and the corresponding surface 19a is a spherical surface or a conical surface in the shape of the ball valve 9. (Tapered surface). Further, the outer peripheral side of the tip portion 19 has a convex conical surface (tapered surface) 19b. Further, the tip portion 19 of the fixed core 6 is provided with a groove 19c by slitting for the fuel passage, so that even when the ball valve 9 is sucked, the fuel passes from the fuel passage 5 through the groove 19c. It flows into the storage space 10 of the ball valve 9.

Further, in the present embodiment, the ball valve 9 is made of a magnetic material such as cast iron or steel, and the surface of the ball valve 9 is subjected to a non-magnetic and high hardness treatment by nitriding the surface thereof. There is. Since only the surface layer of the ball valve 9 is non-magnetic and highly hardened, and the tough structure remains inside, the ball valve 9 has wear resistance and is resistant to fatigue fracture due to impact or repeated stress. Further, the surfaces of the valve seat surface 11 and the contact surface 19a of the fixed core 6 are also subjected to non-magnetic high hardness treatment if necessary. When the surface of the ball valve 9, the valve seat surface 11 and the contact surface 19a of the fixed core 6 are non-magnetically hardened in this way, it is possible to select a material that is not difficult to machine as the material for the ball valve 9 and the fixed core 6, Although it is easy to perform cutting and grinding before surface treatment, it is possible to manufacture an injector that has wear resistance and is resistant to fatigue damage due to impact and repeated stress. As the non-magnetic high hardness treatment, other than the nitriding treatment, other non-magnetic high hardness treatments such as carburizing treatment, hard chrome treatment and Ni-P treatment may be used.

The injector I of the present embodiment configured as described above is attached to the intake pipe of the engine with its nozzle 12 facing, and a signal (pulse current) from the control unit is input through the terminal 17. , The ball valve 9 is reciprocated to inject pressurized fuel. When the electromagnetic coil 3 is demagnetized, the ball valve 9 is pushed back by the return spring 8 and seated on the valve seat 11 to close the valve. However, when the electromagnetic coil 3 is excited, the ball valve 9 is attracted to the fixed core 6. The valve is opened, and the pressurized fuel is discharged from the valve hole 14 into the discharge space portion 15. The discharge space 15 is a space for discharging the discharged fuel in two directions at optimal positions, and the pressurized fuel discharged into the discharge space 15 is atomized and sprayed from the two-hole plate 16 in two directions. At this time, atomization of the discharged fuel is promoted by the air introduced through the assist air introduction hole 12a.

The ball valve 9 reciprocates in a high cycle by a signal (pulse current) from the control unit. The ball valve 9 has a non-magnetic and high hardness surface so that it has abrasion resistance and impact. It is also strong against fatigue failure due to cyclic stress. Furthermore, since the fuel seat projection 13 is provided on the conical valve seat surface 11, the fuel seat property is good against the reciprocal movement of the ball valve 9. Further, since the return spring 8 has a drum shape, the operation stability of the ball valve 9 is improved. Since the assist air introducing hole 12a communicating with the discharge space 15 is formed in the nozzle portion 12, it becomes easy to design the assist air passage for mixing which is conventionally performed after fuel injection.

FIG. 7 shows another embodiment of the present invention, showing another mode of the assist air introducing hole formed in the nozzle portion 12. The four assist air introducing holes 12b of this embodiment are formed so as to be eccentric from the diametrical lines orthogonal to each other, and the swirl effect caused by the eccentric action promotes atomization of the injected fuel. The number and the diameter of the assist air introducing holes 12a and 12b in the above-described embodiment and this embodiment are not limited to the above, and the arrangement is not limited to the center of the discharge space portion 15. It is not limited.

FIG. 8 shows still another embodiment of the present invention, showing another mode of the tip portion of the fixed core 6. In this embodiment, instead of the groove 19c shown in FIGS. 5 and 6, a lateral hole 30 is provided at the tip of the fixed core 6 by lateral hole processing. The fuel from the fuel passage 5 flows into the space 10 through the lateral hole 30, but the outer diameter of the fixed core 6 in front of the lateral hole 30 is larger than that of the bobbin 4 so that the fuel can smoothly flow into the space 10. It is desirable to reduce the diameter so that it is smaller than the inner diameter of the inner hole 2.

C. Effect of the Invention According to the injector for an internal combustion engine of the present invention, only the surface layer of the ball valve is subjected to non-magnetic high hardness treatment, and the tough structure remains inside, so processing such as cutting and grinding before surface treatment is performed. In addition to being easy to wear, it also has wear resistance and is resistant to fatigue failure due to impact and repeated stress. Also, by using a single ball valve, the centripetal action is automatically exerted, there is no misalignment, and the sealing performance is improved. Further, since the fuel seat projection is provided on the conical surface of the valve seat, the fuel sheet has good fuel sheet resistance against the reciprocating movement of the ball valve. Moreover, since the return spring has a drum shape, the operational stability of the ball valve is improved. Further, since the contact surface of the fixed core when sucking the ball valve is a spherical surface or a conical surface that matches the ball shape, the operation of the ball valve is stable.

Furthermore, the operation of the ball valve is further stabilized by subjecting the surface of the valve seat surface and / or the contact surface of the fixed core to non-magnetic high hardness treatment. Further, by providing a groove by slitting the fuel passage at the tip of the fixed core and by providing a lateral hole fuel passage at the tip of the fixed core, the pressurized fuel in the fuel passage prevents suction of the ball valve. It smoothly flows into the space. Further, by providing a discharge space and a 2-hole plate for discharging the discharged fuel in two directions at the optimum position, the pressurized fuel discharged from the valve hole into the discharge space is sprayed in the two directions at the optimum position. ..

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an injector for an internal combustion engine according to an embodiment of the present invention.

FIG. 2 is a front view of a 2-hole plate of an injector for an internal combustion engine according to an embodiment of the present invention.

FIG. 3 is a sectional view of a housing that is a component of the present injector.

FIG. 4 is a sectional view of a return spring that is a component of the present injector.

FIG. 5 is a sectional view of a fixed core that is a component of the present injector.

FIG. 6 is a view taken along the line IV of FIG.

FIG. 7 is a cross-sectional view of a nozzle portion showing another embodiment of the assist air introducing hole according to another embodiment of the present invention.

FIG. 8 is another embodiment of the present invention, which is an enlarged cross-sectional view showing only the tip of the fixed core.

FIG. 9 is a longitudinal sectional view of an injector for an internal combustion engine using a conventional ball valve.

[Explanation of symbols]

1 ... Housing, 2 ... Inner hole, 3 ... Electromagnetic coil, 4 ... Bobbin, 5 ... Shaft hole (fuel passage), 6 ... Fixed core, 8 ... Return spring, 9 ... Ball valve, 11 ... Valve seat surface, 13 ... Fuel seat protrusion, 14 ... Valve hole, 15 ... Discharge space, 16 ... 2-hole plate, 19c ... Groove, 21 ... Fuel filter

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Isamu Sasao 2-110 Kakuta, Gyukan, Kakuda City, Miyagi Prefecture

Claims (5)

[Scope of utility model registration request] 1. A bobbin (4) having a substantially cylindrical housing (1); an inner hole (2) housed in the housing (1), which penetrates in the axial direction in the center, and an electromagnetic coil (3) is wound. A fixed core 6 inserted into the inner hole 2 and having a shaft hole 5 bored in the axial direction thereof and fixed and held by the housing 1; and a return spring 8 facing the fixed core 6. An injector for an internal combustion engine having a ball valve 9 made of a magnetic material, which is disposed through the surface of the ball valve 9, the surface of which is non-magnetic and highly hardened; The valve seat surface 11 has a seat surface 11 and a valve hole 14. The valve seat surface 11 has a conical surface shape, and has a fuel seat projection 13 for enhancing the fuel seat property of the ball valve 9. Has a drum shape, An injector for an internal combustion engine, which is characterized in that 2. A contact surface 1 of a fixed core 6 during suction of a ball valve.
The injector for an internal combustion engine according to claim 1, wherein 9a is a spherical surface or a conical surface that matches the shape of a ball valve. 3. The injector for an internal combustion engine according to claim 1, wherein the surface of the valve seat surface 11 and / or the contact surface 19a of the fixed core 6 is non-magnetic and highly hardened. 4. The housing 1 has a discharge space portion 15 for discharging discharged fuel in two directions at an optimum position in front of the valve hole 14, and a 2-hole plate 16 is provided at an end portion of the discharge space portion 15. The injector for an internal combustion engine according to any one of claims 1 to 3, which is fixed. 5. In the housing 1 of the discharge space portion 15,
The injector for an internal combustion engine according to claim 4, wherein an assist air introduction hole 12a is formed which communicates the outside of the housing 1 with the discharge space portion 15.