JP4285466B2 - solenoid valve - Google Patents

Description

  The present invention relates to an electromagnetic valve used for a fuel injection valve.

2. Description of the Related Art Conventionally, a fuel injection valve that controls the fuel injection timing and the injection amount by an electromagnetic valve is known (see Patent Document 1). For example, as shown in FIG. 4, the electromagnetic valve used for the fuel injection valve includes a solenoid that forms an electromagnet by energizing the electromagnetic coil 100, and the solenoid is housed in a cylindrical case 120 together with the housing 110, It is attached to the injector body 130 via the case 120.
By the way, in a structure that requires a liquid seal such as fuel, an O-ring is often used. Also in the above solenoid valve, the housing 110 and the case 120 and the case 120 and the injector body 130 are sealed by O-rings 140 and 150.
JP 2001-102124 A

The above O-rings are generally inexpensive, but when used for products exposed to high temperatures such as solenoid valves used for fuel injection valves, a material with excellent heat resistance is required. Expensive.
Further, when using an O-ring, the groove processing of the portion where the O-ring is inserted, the surface roughness processing of the metal surface, and the management of scratches on the O-ring are also factors that increase the cost.
In addition, when the seal part is composed of metal parts like the above solenoid valve, it is often fastened by caulking (part A in the figure) and the structure becomes complicated, which causes an increase in cost. It has become.
The present invention has been made based on the above circumstances, and an object of the present invention is to provide a technology capable of realizing metal parts fixing and fuel sealing at low cost in an electromagnetic valve used for a fuel injection valve. .

(Invention of Claim 1)
The present invention is an electromagnetic valve used in a fuel injection valve, which is a solenoid that magnetizes a stator by energizing an electromagnetic coil to attract an armature, a metal housing disposed on the side opposite to the armature of the stator, and a stator A cylindrical metal case that holds and fixes the stator between the housing and the housing, and the case has an anti-armature side end extending beyond the stator to the housing side, It is characterized by being welded to the outer peripheral surface of the housing over the entire circumference so that a fuel seal with the housing can be realized without using an O-ring between the housing and the housing .

According to the present invention, since the case and the housing are welded over the entire circumference, a fuel seal between them (between the case and the housing) can be achieved without using an O-ring.
Further, since the O-ring is not used, it is not necessary to perform groove processing of the portion where the O-ring is inserted, surface roughness processing of the metal surface, and management of scratches on the O-ring. Further, since it is not necessary to perform caulking as a fixing means for the case and the housing, the structure can be simplified.
As described above, the case and the housing are welded all around, so that the caulking process is not necessary, and at the same time, the function of the fuel seal can be provided, so that the metal parts can be fixed and the fuel seal can be realized at low cost. .

(Invention of Claim 2)
The present invention is an electromagnetic valve used in a fuel injection valve, which is a solenoid that magnetizes a stator by energizing an electromagnetic coil to attract an armature, a metal housing disposed on the side opposite to the armature of the stator, and a stator A cylindrical metal case that holds and fixes the stator between the housing and a metal body that fits to the outer periphery of the case. In order to realize a fuel seal with the case without using an O-ring, it is welded to the outer peripheral surface of the case over the entire circumference.

According to the present invention, since the case and the body are welded over the entire circumference, a fuel seal between them (between the case and the body) can be achieved without using an O-ring.
Further, since the O-ring is not used, it is not necessary to perform groove processing of the portion where the O-ring is inserted, surface roughness processing of the metal surface, and management of scratches on the O-ring. Furthermore, since it is not necessary to fasten the case and body with a nut or the like, the structure can be simplified.
As mentioned above, the case and body are welded around the circumference, so there is no need for fastening with nuts and the like, and at the same time the fuel seal function can be provided, so metal parts can be secured together and the fuel seal can be made at low cost. realizable.

(Invention of Claim 3)
The present invention is an electromagnetic valve used in a fuel injection valve, which is a solenoid that magnetizes a stator by energizing an electromagnetic coil to attract an armature, a metal housing disposed on the side opposite to the armature of the stator, and a stator A cylindrical metal case that holds and fixes the stator between the housing and a metal body that fits on the outer periphery of the case, and the case has an end on the side opposite to the armature. The part extends beyond the stator to the housing side, and is welded to the outer peripheral surface of the housing over the entire circumference so that a fuel seal with the housing can be realized without using an O-ring between the housing, body, without using the O-ring between the case, as can be realized fuel seal between the case and the outer peripheral surface of the case is welded over the entire periphery It is characterized in.

According to the present invention, the case, the housing, and the case, and the body are welded over the entire circumference, so that the fuel seal between the case and the housing and between the case and the body is used without using an O-ring. Can do.
Further, since the O-ring is not used, it is not necessary to perform groove processing of the portion where the O-ring is inserted, surface roughness processing of the metal surface, and management of scratches on the O-ring. Furthermore, it is not necessary to perform caulking as a fixing means between the case and the housing, and it is not necessary to fasten with a nut or the like as a fixing means between the case and the body, so that the structure can be simplified.
As mentioned above, the case and housing, and the case and body are welded all around, eliminating the need for caulking and fastening with nuts, etc., and at the same time providing a fuel seal function. In addition, the fuel seal can be realized at a low cost.

(Invention of Claim 4)
The electromagnetic valve according to claim 1 is characterized in that the case is fitted inside a cylindrical body via a seal member.

(Invention of Claim 5)
5. The electromagnetic valve according to claim 1, wherein the stator has a spring chamber formed in a central portion in a radial direction, and a spring for urging the armature in the anti-stator direction is disposed in the spring chamber. Is formed with a through hole penetrating the armature from the suction surface sucked by the stator to the anti-suction surface, and further, a communication groove communicating the through hole and the spring chamber is formed on the suction surface. .
According to the present invention, when the armature is attracted to the magnetized stator and moves through the fuel at a high speed, the fuel in the spring chamber can escape through the communication groove and the through hole. Thereby, the fluid drag generated when the armature moves through the fuel at high speed can be reduced, and a stable response can be ensured.

  The best mode for carrying out the present invention will be described in detail with reference to the following examples.

FIG. 1 is a cross-sectional view of a solenoid valve 1 according to the first embodiment.
The electromagnetic valve 1 of the present embodiment is used, for example, in a fuel injection valve (not shown) of a common rail fuel injection system, and controls the injection timing and the injection amount of fuel injected into an internal combustion engine (for example, a diesel engine).
The fuel injection valve includes a needle that opens and closes the nozzle hole, a pressure chamber that stores back pressure of the needle (hydraulic pressure that urges the needle in the valve closing direction), and a pressure that opens the hydraulic pressure of the pressure chamber to the low pressure side. It comprises an open passage 2 (see FIG. 1) and the electromagnetic valve 1 of the present invention that intermittently connects between the pressure release passage 2 and the pressure chamber. The structure of the fuel injection valve excluding the electromagnetic valve 1 is well known and will not be described in detail.

The electromagnetic valve 1 has a solenoid (described below) that drives the ball valve 3 using the attractive force of the electromagnet, and this solenoid, together with the orifice plate 4, the housing 5, the case 6, and the like, It arrange | positions at the cylindrical wall part 7a provided in the upper end part.
The solenoid includes an electromagnetic coil 8, a stator 9, an armature 10, a valve body 11, and the like.
The electromagnetic coil 8 is wound around a resin bobbin 12, inserted into the stator 9, and resin molded. The electromagnetic coil 8 has one coil end taken out from the bobbin 12 connected to a rod-like lead terminal 13 and electrically connected to a terminal 15 held by a connector 14 via the lead terminal 13. Yes. The other coil end is grounded via the injector body 7.
The connector 14 is resin-molded with the housing 5 serving as a base as an insert.

The stator 9 is formed of, for example, a ferromagnetic material such as iron and is magnetized by energizing the electromagnetic coil 8 to form an electromagnet. A center hole is formed in the stator 9 so as to penetrate the central portion in the radial direction in the vertical direction in the figure, and a cylindrical member 16 is inserted into the inner periphery of the center hole.
The cylindrical member 16 forms a spring chamber 18 for disposing the spring 17 on the inner side, and the lower end surface of the cylindrical member 16 is formed as a stopper surface of the armature 10. A spring shim 19 that adjusts the compressive load of the spring 17 is disposed at the upper end of the spring chamber 18 in the figure.

  The armature 10 is disposed in a valve chamber 20 formed between the stator 9 and the valve body 11 and filled with fuel. The armature 10 is urged downward in the figure by receiving the compression load of the spring 17. The armature 10 is integrally provided with a shaft portion 21 projecting toward the counter-stator side (the lower side in the drawing) at the center in the radial direction, and the shaft portion 21 is slidably held by the valve body 11. A ball valve 3 that opens and closes an outlet orifice 22 that communicates with the pressure chamber is held at the tip of the shaft portion 21.

  Further, the armature 10 is formed with a through hole 10a penetrating from the suction surface (upper end surface in FIG. 1) facing the stator 9 to the opposite suction surface, and the through hole 10a and the spring chamber 18 are communicated with each other. A communication groove (not shown) is recessed in the suction surface. As a result, when the armature 10 is attracted by the stator 9 and moved at a high speed, the fuel in the spring chamber 18 can escape to the valve chamber 20 through the communication groove and the through hole 10a. Drag can be reduced and stable response can be secured.

  The valve body 11 is disposed on the upper side of the orifice plate 4 inside the cylindrical wall portion 7a provided on the injector body 7, and is fixed to the cylindrical wall portion 7a by screwing. The valve body 11 is provided with a vertical hole 23 communicating with the valve chamber 20 and a communication passage 24 connected to the vertical hole 23, and the ball valve 3 provides a space between the communication passage 24 and the outlet orifice 22. Intermittently.

The orifice plate 4 is formed with the pressure chamber, an inlet orifice (not shown) for introducing high-pressure fuel into the pressure chamber, and an outlet orifice 22.
The housing 5 is made of metal such as iron or stainless steel, is disposed on the side opposite to the armature of the stator 10, and is fixed to the case 6. The housing 5 is formed with a through hole for taking out the lead terminal 13 and the pressure release passage 2, and the pressure release passage 2 communicates with the spring chamber 18.
The lead terminal 13 is supported via a pair of bushes (insulating materials) 25 inserted into the through holes, and a liquid between the through hole and the lead terminals 13 is supported by an O-ring 26 disposed between the bushes 25. It is tightly sealed.

  Similar to the housing 5, the case 6 is made of metal such as iron or stainless steel, and is provided in a cylindrical shape surrounding the periphery of the stator 9. The case 6 is provided in a bowl shape in which the lower end portion in the drawing extends from the outer peripheral surface of the stator 9 to the bottom surface (the end surface on the opposite side of the housing), and the upper end portion in the drawing extends beyond the stator 9 to the housing 5 side. It is welded to the outer peripheral surface of the housing 5 over the entire circumference. As a result, the stator 9 is fixed between the housing 5 and the case 6, and a subassembly excluding the armature 10 and the valve body 11 is formed.

  This sub-assembly is assembled by screwing the valve body 11 inside the cylindrical wall portion 7a of the injector body 7 and then inserting a shim 27 between the valve body 11 and the case 6 to the inner side of the cylindrical wall portion 7a. The nut 28 is coupled and fixed to the male screw portion 7b formed on the outer periphery of the cylindrical wall portion 7a. An O-ring 29 is attached to the outer peripheral surface of the case 6 inserted inside the cylindrical wall portion 7a, and the space between the case 6 and the cylindrical wall portion 7a is sealed by the O-ring 29.

Next, the operation of the fuel injection valve will be described.
When the electromagnetic coil 8 is energized and the stator 9 is magnetized, an attractive force acts between the stator 9 and the armature 10, so that the armature 10 is against the biasing force of the spring 17 (see FIG. 1). To the top). When the ball valve 3 opens the outlet orifice 22 by the movement of the armature 10, the hydraulic pressure of the pressure chamber passes through the outlet orifice 22 → the communication path 24 → the vertical hole 23 → the valve chamber 20 → the spring chamber 18 → the pressure release path 2. Open to the low pressure side.
As a result, when the back pressure of the needle is reduced and the hydraulic pressure that urges the needle in the valve opening direction overcomes the force that urges the needle in the valve closing direction, the needle lifts up from the nozzle hole. Fuel is injected.

  Thereafter, when the energization to the electromagnetic coil 8 is stopped and the attractive force disappears, the armature 10 is pushed back to the spring 17 and the ball valve 3 closes the outlet orifice 22 so that the hydraulic pressure in the pressure chamber rises again. As a result, when the force that urges the needle in the valve closing direction overcomes the oil pressure that urges the needle in the valve opening direction, the needle is pushed back, and the fuel passage leading to the injection hole is blocked, thereby causing the injection. finish.

(Effect of Example 1)
The solenoid valve 1 described in the first embodiment uses an O-ring (particularly a relatively expensive O-ring having heat resistance) because the end of the case 6 is welded to the entire outer peripheral surface of the housing 5. In addition, a fuel seal between the two (between the case 6 and the housing 5) can be achieved.
Further, since the O-ring is not used, it is not necessary to perform groove processing of the portion where the O-ring is inserted, surface roughness processing of the metal surface, and management of scratches on the O-ring. Furthermore, as a means for fixing the case 6 and the housing 5, for example, it is not necessary to perform a caulking process (A portion in the figure) as shown in FIG. 4, so that the structure can be simplified.
In this way, the case 6 and the housing 5 are welded all around so that the caulking process is unnecessary, and at the same time, the function of the fuel seal can be provided. Therefore, when compared with the conventional structure shown in FIG. Fixing of parts (case 6 and housing 5) and fuel sealing can be realized at low cost.

FIG. 2 is a cross-sectional view of the solenoid valve 1 according to the second embodiment.
As shown in FIG. 2, the electromagnetic valve 1 shown in the second embodiment is an example in which the cylindrical wall portion 7 a of the injector body 7 is fixed to the outer peripheral surface of the case 6 by welding all around.
However, the case 6 and the housing 5 are fixed by caulking and are fuel-sealed by an O-ring 30 as in the conventional structure shown in FIG.
In this case, the cylindrical wall portion 7a is welded to the outer peripheral surface of the case 6 so that a fuel seal between them can be realized, and the sub-assembly can be securely fixed to the injector body 7, so that it is described in the first embodiment. The O-ring 29 is unnecessary, and the nut 28 for fixing the subassembly to the injector body 7 is also unnecessary. As a result, there is no need for groove processing for inserting an O-ring on the outer periphery of the case 6, and it is not necessary to form the male screw portion 7b (see FIG. 1) on the outer periphery of the cylindrical wall portion 7a. . Thereby, fixation of metal parts (case 6 and cylindrical wall part 7a) and the fuel seal between both are realizable at low cost.

FIG. 3 is a cross-sectional view of the solenoid valve 1 according to the third embodiment.
The solenoid valve 1 shown in the third embodiment is an example in the case of having both the configuration described in the first embodiment and the configuration described in the second embodiment as shown in FIG.
That is, the case 6 and the housing 5 and the case 6 and the cylindrical wall portion 7a of the injector body 7 are all welded around the circumference. Thereby, fixation of metal parts (case 6 and housing 5, case 6 and cylindrical wall part 7a), and a fuel seal between both are realizable at low cost.

(Example 1) which is sectional drawing of a solenoid valve. (Example 2) which is sectional drawing of a solenoid valve. (Example 3) which is sectional drawing of a solenoid valve. It is sectional drawing of a solenoid valve (prior art).

Explanation of symbols

1 Solenoid valve 5 Housing 6 Case 7 Injector body (body)
8 Electromagnetic coil 9 Stator 10 Armature 10a Through-hole penetrating the armature 17 Spring 18 Spring chamber 29 O-ring (seal member)

Claims (5)

An electromagnetic valve used for a fuel injection valve,
A solenoid that magnetizes the stator by energizing the electromagnetic coil to attract the armature;
A metal housing disposed on the side opposite to the armature of the stator;
A cylindrical metal case for holding the outer periphery of the stator and fixing the stator sandwiched between the housing and
The case has an end on the side opposite to the armature that extends beyond the stator to the housing side so that a fuel seal with the housing can be realized without using an O-ring between the case and the housing. The solenoid valve is welded to the outer peripheral surface of the housing over the entire circumference. An electromagnetic valve used for a fuel injection valve,
A solenoid that magnetizes the stator by energizing the electromagnetic coil to attract the armature;
A metal housing disposed on the side opposite to the armature of the stator;
A cylindrical metal case for holding the outer periphery of the stator and sandwiching and fixing the stator between the housing and
With a metal body that fits on the outer periphery of this case,
The body is welded to the outer peripheral surface of the case over the entire circumference so as to realize a fuel seal with the case without using an O-ring between the body and the case. solenoid valve. An electromagnetic valve used for a fuel injection valve,
A solenoid that magnetizes the stator by energizing the electromagnetic coil to attract the armature;
A metal housing disposed on the side opposite to the armature of the stator;
A cylindrical metal case for holding the outer periphery of the stator and sandwiching and fixing the stator between the housing and
With a metal body that fits on the outer periphery of this case,
The case has an end on the side opposite to the armature that extends beyond the stator to the housing side so that a fuel seal with the housing can be realized without using an O-ring between the case and the housing. , Welded to the outer peripheral surface of the housing over the entire circumference,
The body is welded to the outer peripheral surface of the case over the entire circumference so as to realize a fuel seal with the case without using an O-ring between the body and the case. solenoid valve. The solenoid valve according to claim 1,
The electromagnetic valve according to claim 1, wherein the case is fitted inside a cylindrical body through a seal member. In any one of the solenoid valves according to claims 1 to 4,
In the stator, a spring chamber is formed in a central portion in the radial direction, and a spring for urging the armature in the anti-stator direction is disposed in the spring chamber.
The armature is formed with a through-hole penetrating the armature from a suction surface sucked by the stator to an anti-suction surface, and further a communication groove is formed in the suction surface to communicate the through-hole and the spring chamber. A solenoid valve characterized by that.

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