JP2002349745A - Solenoid valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify part constitution by imparting a plurality of functions to one member. SOLUTION: This solenoid valve 30 is fixed to an injector body 11 by a retaining nut 31. A movable member 40 oppositely reciprocating to a core 43 is housed in a valve cylinder 32 of the solenoid valve 30. The movable member 40 is composed of an armature part 41 and a sliding shaft part 42. A spherical member 36 for constituting a separate valve member is arranged on the tip (the lower end of a drawing) of the sliding shaft part 42. The movable member 40 is composed of a soft magnetic material, and a thin hardened layer by surface treatment or heat treatment is arranged on the surface. When carrying an electric current to a coil 44, the armature part 41 is attracted to the core 43, the movable member 40 moves, and the spherical member 36 moves to a valve opening position according to the movement.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solenoid valve, and is embodied, for example, in an injector for injecting fuel into an engine.

[0002]

2. Description of the Related Art A solenoid valve of this type is used for an injector or the like in a fuel injection device for a diesel engine, and as an example, a solenoid valve shown in FIG. 5 is known (for example, a solenoid valve disclosed in Japanese Patent Application Laid-Open No. 10-153154). ). Note that FIG.
It is sectional drawing which extracts and shows only the electromagnetic valve part in the injector of an electromagnetic drive type.

The solenoid valve 70 shown in FIG. 5 is a two-way solenoid valve for controlling the fuel pressure in the pressure control chamber 78. The needle valve (not shown) moves by leaking the fuel pressure in the pressure control chamber 78. Fuel injection is performed from an injector injection hole. Specifically, the coil 72 is a core 71
When the coil 72 is energized, a magnetic path is formed between the core 71 and the armature 73, and the core 71
Between the armature 73 and the armature 73. Here, the armature 73 is joined to the sliding member 74, and when the coil is energized, the armature 73 and the sliding member 74 move upward in the figure against the urging force of the spring 75.

The sliding member 74 presses a spherical member 76 which is a separate valve member. When the coil 72 is not energized, the spherical member 76 is biased by a spring 75.
Is pressed downward in the figure. As a result, the throttle hole 77 is closed, and the high-pressure fuel in the pressure control chamber 78 is held as it is. At this time, fuel injection by the injector is not performed. On the other hand, when the coil 72 is energized, the spherical member 76 moves with the attraction of the armature 73 and the throttle hole 77
Is released. Thereby, the high-pressure fuel in the pressure control chamber 78 leaks, and the fuel is injected by the injector.

[0005]

In the above-mentioned solenoid valve 70,
The armature 73 is a component that forms a magnetic circuit, and is therefore made of a soft magnetic material such as pure iron. Also,
The sliding member 74 has been used after quenching and tempering to improve wear resistance and reduce frictional force. In such a case, the armature 73 made of a soft magnetic material is made of a separate part because it cannot be quenched because of deteriorating magnetic properties, and the two members 73 and 74 are integrated by a method such as press fitting or welding. I was As described above, it is difficult to reduce the number of parts in the conventional solenoid valve 70,
There is a problem that the manufacturing cost increases due to the increase in the number of parts.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a single member with a plurality of functions, thereby simplifying the component configuration. It is to provide a solenoid valve.

[0007]

The solenoid valve according to the present invention comprises a core member and a movable member which reciprocates in opposition to the core member. The movable member moves. Further, with the movement of the movable member, a valve member different from the movable member operates. In particular, claim 1
The armature function for forming a magnetic path and the sliding function for reciprocating motion are integrally added to the movable member. That is, the sliding member and the armature portion, which are conventionally provided separately, are integrated by the same member. As a result, a plurality of functions can be provided to one member, thereby simplifying the component configuration.

In the electromagnetic valve according to the second aspect, the movable member is made of a soft magnetic material, and a hardened layer formed by a surface treatment or a heat treatment is provided on the surface thereof. In this case, by setting the material of the movable member to a soft magnetic material, good magnetic characteristics can be provided. Also, the surface of the movable member (sliding surface)
By providing a hardened layer, the wear resistance can be improved and the frictional force can be reduced, and the sliding function of the movable member can be improved. Therefore, it is possible to realize a favorable opening / closing operation of the solenoid valve while simplifying the configuration.

Here, it is desirable to perform soft nitriding as a heat treatment to be performed on the movable member and the case member.
It is preferable to form a hardened layer (thin hardened layer) of about several μm on the member surface by the soft nitriding.

[0010] As described in claim 4, the movable member includes a sliding shaft portion and an armature portion, and the hardened layer is preferably provided only on the surface of the sliding shaft portion. In this case, the effect on the armature function due to the provision of the hardened layer by the surface treatment or the heat treatment can be suppressed more reliably.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. In the present embodiment,
The present invention is embodied in a common rail type fuel injection device for a diesel engine. This will be described in detail.

FIG. 1 is a sectional view showing the overall configuration of the injector. In the injector 10 of FIG. 1, an intake port 12 is provided in an injector body 11, and high-pressure fuel is introduced from a common rail (not shown) through a fuel filter (not shown) of the intake port 12.

A nozzle body 13 is provided on the injection hole side of the injector 10, and the injector body 11 and the nozzle body 13 are connected by a retaining nut 15 with a packing tip 14 interposed therebetween. In the nozzle body 13,
A needle valve 20 for opening and closing the injection hole 13a is housed in a reciprocating manner.

A pressure pin 21 is provided on the side of the needle valve 20 opposite to the injection hole, and a control piston 22 for contacting or connecting with the pressure pin 21 is provided on the side of the pressure pin 21 opposite to the injection hole. . The pressure pin 21 is inserted through a spring 23, and the spring 23 urges the pressure pin 21 downward in FIG. 1, that is, in the injection hole closing direction (valve closing direction). Reference numeral 25 denotes a plurality of spacers for adjusting the set load of the spring 23. A pressure control chamber 27 is provided on the side of the control piston 22 opposite to the injection hole.

The high-pressure fuel introduced from the suction port 12 branches into high-pressure fuel passages 28 and 29, respectively. The high-pressure fuel branched to the high-pressure fuel passage 28 is supplied to a fuel reservoir 24 formed annularly around the needle valve 20, and the high-pressure fuel branched to the high-pressure fuel passage 29 is supplied to the pressure control chamber 27. The pressure of the high-pressure fuel in the fuel reservoir 24 urges the needle valve 20 upward in FIG. 1, that is, in the lift direction in which the fuel reservoir 24 and the injection hole 13a communicate with each other, and the pressure control chamber 2
The pressure of the high-pressure fuel in the control piston 22 is controlled downward in FIG. 1, that is, in the direction in which the needle valve 20 closes the injection hole 13a.
Energize.

A solenoid valve 30 is mounted on the upper part of the figure of the injector 10, and details thereof will be described with reference to FIG. The solenoid valve 30 includes a retaining nut 31.
Is fixed to the injector body 11 by the valve cylinder 32 of the solenoid valve 30 and the injector body 11.
The first diaphragm plate 33 and the second diaphragm plate 34 are sandwiched between them. The valve cylinder 32 has a cylindrical space in the center, and the space serves as a low-pressure fuel chamber 35. The first aperture plate 33 and the second aperture plate 34 are provided with aperture holes 33a and 34a, respectively.
The flow rate of fuel flowing from the high pressure fuel passage 29 into the pressure control chamber 27 is regulated by 3a, and the flow rate of fuel flowing from the pressure control chamber 27 to the low pressure fuel chamber 35 is regulated by the throttle hole 34a.

The low-pressure fuel chamber 35 is provided with a spherical member 36 constituting a valve member. The spherical member 36 has a structure in which a flat portion is processed into a part of a sphere, and the flat portion of the spherical member 36 is always formed by the aperture 34 a of the second aperture plate 34.
Faces. The flat part of the spherical member 36 is the second diaphragm plate 34
, The communication between the low-pressure fuel chamber 35 and the pressure control chamber 27 is interrupted. The spherical member 36 is made of ceramic so as to prevent abrasion at the contact portion between the spherical member 36 and the second diaphragm plate 34, while the contact surface of the second diaphragm plate 34 is hardened (CrN coating or the like). ) Is given.

A cylindrical sliding cylinder 37 is fixed to the valve cylinder 32, and a movable member 40 is slidably disposed in the sliding cylinder 37. The movable member 40 includes an armature portion 41 and a sliding shaft portion 42, and the sliding shaft portion 4
2 is formed at the tip (lower end in the figure) of a concave portion having a V-shaped cross section, and the spherical member 36 is disposed in the concave portion. In the present embodiment, in order to improve the adhesion of the contact surface between the spherical member 36 and the second diaphragm plate 34, the spherical member 36
Is provided separately from the movable member 40. The armature 41 is opposed to the core 43, and when the coil 44 is energized, the armature 41 is attracted to the core 43. Here, an annular space is provided in the core 43, and the coil 44 is wound around the space. The core 43 is a cylinder 4
5 is fixed by welding or the like.

A spring 4 is provided in a space 45a of the cylindrical body 45.
The movable member 40 is urged downward by a spring 47 via a pressing member 46.
Reference numeral 48 denotes an adjusting member for setting the urging force of the spring 47.

Here, the fuel in the low-pressure fuel chamber 35 flows into the space 45a of the cylinder 45 via a low-pressure fuel passage (not shown) provided in the valve cylinder 32. Further, the fuel is discharged to the outside of the injector via the adjusting member 48 and the low-pressure fuel passage 49 for collecting leaked fuel. Reference numeral 50 denotes a connector for receiving a control signal from an ECU (electronic control unit).

Incidentally, the injector body 11 of FIG. 1 is provided with a low-pressure fuel passage (not shown) for collecting fuel leaked from the sliding clearance of the control piston 22 and the needle valve 20. Leakage fuel from the sliding clearance between the control piston 22 and the needle valve 20 is once collected in the spring chamber 26, and then supplied to the low-pressure fuel chamber 35 via a low-pressure fuel passage (not shown). The fuel is supplied to the space 45a of the cylindrical body 45 and the adjusting member 4 as described above.
The fuel is discharged to the outside of the injector via the low pressure fuel passage 8 and a low-pressure fuel passage 49 for collecting leaked fuel.

Next, the operation of the injector 10 will be described. When the power to the coil 44 is turned off, the spring 4
The urging force of 7 pushes the movable member 40 downward in FIGS. 1 and 2. Therefore, the spherical member 36 is seated on the second throttle plate 34, and the communication between the pressure control chamber 27 and the low-pressure fuel chamber 35 is cut off. At this time, the injection hole 13a is closed by the needle valve 20, and fuel injection is not performed.

When the power supply to the coil 44 is turned on, an electromagnetic force for attracting the armature 41 is generated. When the sum of the electromagnetic force and the fuel pressure in the pressure control chamber 27 becomes larger than the urging force of the spring 47, the movable member 40 is lifted, and the spherical member 36 is separated from the second diaphragm plate 34. Thus, the throttle hole 34a communicates with the low-pressure fuel chamber 35, and the pressure control chamber 2
The fuel No. 7 flows out to the low-pressure fuel chamber 35. At this time,
Since the fuel pressure in the pressure control chamber 27 decreases, the force pressing the control piston 22 in the nozzle hole closing direction decreases. Therefore,
The needle valve 20 is lifted, and fuel is injected from the injection hole 13a.

When the above state continues and a predetermined injection end timing is reached, the power supply to the coil 44 is turned off and the spring 47 is turned off.
The solenoid valve 30 is closed by the urging force. Then, from the high-pressure fuel passage 29 through the throttle hole 33a, the pressure control chamber 27
High-pressure fuel flows into the pressure control chamber 27, and the pressure in the pressure control chamber 27 rises. As a result, the force pressing the control piston 22 in the injection hole closing direction increases, and the needle valve 20 closes the injection hole 13a, and the injection ends.

Incidentally, in the solenoid valve 30 of the present embodiment,
The movable member 40 has an armature function for forming a magnetic path in addition to the sliding function. The movable member 40 is configured as follows in order to make the two functions compatible.

That is, the movable member 40 is made of a soft magnetic material such as pure iron or low carbon steel in order to achieve both the armature function and the sliding function by one member. In addition, this soft magnetic material cannot be subjected to heat treatment such as quenching because it deteriorates magnetic properties, but is required to have improved wear resistance, reduced frictional force, and improved surface hardness. Therefore, NiP plating (nickel
(Phosphorus plating), and a thin cured layer is provided on the surface.

In this case, the hardness distribution from the member surface is shown in FIG.
B. That is, only the surface of the movable member 40 is hardened, unlike the case of a general heat hardening process such as quenching (a in the figure).

When the movable member 40 is subjected to a thermosetting treatment such as quenching, the relationship between the ampere turn (the number of amps) and the suction force is as shown in FIG. On the other hand, when only the surface of the movable member 40 is cured as described above, the suction force increases as shown in FIG. This is because the entire structure of the armature portion 41 is magnetically degraded when a heat hardening treatment such as quenching is performed, whereas when only the surface is hardened, the deep internal structure of the armature portion 41 is not deteriorated. This is because the magnetic characteristics of the sample 41 hardly deteriorate. As a result, it is possible to improve the wear resistance and reduce the frictional force while maintaining the magnetic characteristics.

As another curing treatment, the movable member 40 may be subjected to soft nitriding. This soft nitriding is a kind of heat treatment, and a hardened layer (compound layer) is formed on the surface of the movable member 40.
Is formed to a thickness of about 7 to 20 μm, and a diffusion layer
０．２0.2 mm. In this case, the surface hardness is Hv4
It is about 50 to 650 or more. Further, a ceramic coating such as DLC (diamond-like carbon) may be applied. DLC indicates coating thickness 2
At 〜4 μm, the surface hardness is very high, Hv 2000-3000. In any case, it is possible to improve the wear resistance and reduce the frictional force while maintaining the magnetic characteristics of the movable member 40.

Incidentally, when a thin hardened layer is provided on the surface of the movable member 40 by surface treatment or heat treatment, such hardening may be applied to the entire surface, or the hardened layer may be provided on a surface other than the sliding surface (the surface of the sliding shaft portion 42). Other than that, masking may be performed, and only the sliding surface (the surface of the sliding shaft portion 42) may be hardened. When the hardening treatment is performed only on the sliding surface, the influence on the armature function can be suppressed more reliably. Further, the depth of the hardened layer may be different between the sliding surface and the other.

According to the embodiment described above, the following effects can be obtained. In the solenoid valve 30 of the present embodiment, since the movable member 40 is configured to have both the sliding function and the armature function, a plurality of functions are integrated into one member (the movable member 40), thereby simplifying the component configuration. Can be achieved. In this case, since the number of parts can be reduced, the cost can be reduced.

The movable member 40 is made of a soft magnetic material, and a hardened layer is provided on the surface of the movable member 40 by surface treatment or heat treatment.
Can be realized.

The present invention can be embodied in the following modes other than the above. Although the normally closed solenoid valve in which the valve member (spherical member 36 in FIG. 2) is held in the closed position when the coil is not energized is illustrated, the valve member may be opened when the coil is not energized. May be embodied as a normally open solenoid valve that is held in the solenoid valve. Further, in the above embodiment, the ON / OFF type solenoid valve in which the valve member moves at two positions of the valve opening position and the valve closing position has been embodied. However, a linear solenoid valve (proportional solenoid valve) may be used. good.

In the above embodiment, the spherical member 36 is used as the valve member pressed by the movable member. However, the form of the valve member may be arbitrary. By changing the form of the valve member, it is possible to cope with various variations as an electromagnetic valve.

In the above embodiment, the present invention is embodied as a solenoid valve of an injector, but other embodiments are also possible. For example, the present invention may be applied to an electromagnetic valve for controlling a fuel flow rate of a high-pressure pump, or may be applied to an electromagnetic valve of a brake device including an ABS (anti-lock brake system) or another device.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of an injector according to the present invention.

FIG. 2 is an enlarged sectional view showing a configuration of a solenoid valve.

FIG. 3 is a diagram showing a relationship between a depth from a member surface and a material hardness.

FIG. 4 is a diagram showing a relationship between an ampere turn and a suction force.

FIG. 5 is a cross-sectional view showing a configuration of a solenoid valve according to the related art.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Injector, 30 ... Solenoid valve, 36 ... Spherical member (valve member), 40 ... Movable member, 41 ... Armature part, 4
2 ... sliding shaft part, 43 ... core, 44 ... coil.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shigeru Enomoto 14 Iwatani, Shimowakaku-cho, Nishio City, Aichi Prefecture Inside the Japan Automobile Parts Research Laboratory (72) Inventor Moriyasu Goto 14 Iwatani, Shimowakaku-cho, Nishio City, Aichi Prefecture Japan Auto Parts Research Institute (72) Inventor Yoshihiro Tsuzuki 1-1-1, Showa-cho, Kariya-shi, Aichi F-term in Denso Corporation (Reference) 3G066 AA07 AB02 AC09 BA61 CC05U CC08T CC14 CC15 CD18 CD21 CE22 CE24 CE31 3H106 DA07 DA13 DA23 DB02 DB12 DB26 DB32 DC04 DC06 DC17 DD03 EE04 EE34 GA15 GA16 JJ02 KK18

Claims (4)

[Claims] A movable member that reciprocates in opposition to the core member, a magnetic path is formed by energizing a coil, the movable member moves, and the movable member moves. A solenoid valve for operating a valve member different from the movable member, wherein a sliding function for reciprocating motion and an armature function for forming a magnetic path are integrally added to the movable member. Solenoid valve characterized by the following. 2. The solenoid valve according to claim 1, wherein said movable member is made of a soft magnetic material, and a surface thereof is provided with a hardened layer by surface treatment or heat treatment. 3. The electromagnetic valve according to claim 2, wherein a hardened layer of about several μm is formed on the surface of the member by nitrocarburizing. 4. The solenoid valve according to claim 2, wherein
The movable member includes a sliding shaft portion and an armature portion,
An electromagnetic valve provided with the cured layer only on the surface of the sliding shaft.