JP2000240525A - Solenoid valve and fuel injection valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce size and improve operation responsiveness of a movable valve which generates electromagnetic attraction by a magnetic circuit having two air gaps by improving generation efficiency of the electromagnetic attraction while reducing valve operation voltage. SOLUTION: In this solenoid valve, a magnetic circuit M which generates electromagnetic attraction applied to a movable valve 14, through current carrying to a solenoid coil 4 has air gaps G1, G2. In such a case, a permeance ratio P2/P1 (permeance P2 at air gap G2 is divided by permeance P1 at air gap G1) ranges between 1.5 and 2.1 where P1 is premeance at the air gap G1, and P2 is permeance at the air gap G2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a solenoid valve and a fuel injection valve.

[0002]

2. Description of the Related Art Conventional solenoid valves, for example, fuel injection valves, include:
A movable valve is supported by a leaf spring so as to be openable and closable, and the movable valve overcomes the spring load of the leaf spring and is moved by an electromagnetic attraction force generated by energization of a solenoid coil (for example, JP-A-4-31662). reference). In such a fuel injection valve, the magnetic circuit that generates the electromagnetic attraction has two air gaps between the movable valve and the magnetic path forming member.

[0003]

In the conventional fuel injection valve, the electromagnetic attraction generated by energizing the solenoid coil is proportional to the area of the air gap between the movable valve and the magnetic path forming member. Therefore, in order to improve the operation responsiveness of the movable valve, the facing area between the movable valve and the magnetic path forming member may be increased to increase the electromagnetic attraction force.

However, the method of simply increasing the opposing area between the movable valve and the magnetic path forming member in each air gap imposes a limitation on mounting on an engine because the size of the fuel injection valve must be increased. It is not desirable for the fuel injection valve to receive. Further, the operating voltage (also referred to as a valve operating voltage) required for operating the movable valve increases, so that the efficiency of generating the electromagnetic attraction force is reduced.

Accordingly, the present applicant has proposed the present invention focusing on permeance in each air gap. The permeance, as is well known, indicates the ease with which magnetic flux flows. The higher the permeance, the greater the electromagnetic attraction, and the smaller the permeance, the smaller the electromagnetic attraction. Permeance (P) is represented by P = (μ · S) / L. Here, μ is the magnetic permeability, S is the facing area, L
Is the facing distance of the air gap.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a magnetic circuit having two air gaps for applying an electromagnetic attraction force acting on a movable valve. The electromagnetic valve and the fuel injection valve, which can improve the efficiency of generating electromagnetic attraction force while reducing the valve operating voltage, thereby reducing the size and improving the operation response of the movable valve. To provide.

[0007]

According to a first aspect of the present invention, a magnetic circuit for generating an electromagnetic attraction force acting on a movable valve by energizing a solenoid coil comprises a magnetic circuit inside the solenoid coil. a forming member and the air gap G ₁ is formed between said movable valve, and the air gap G ₂ is formed between the magnetic path forming member and the movable valve in the outside of the air gap G _1, the in the solenoid valve having an air gap of 2 points, permeance ratio permeance P ₂ in the air gap G ₂ by dividing the permeance P ₁ in the air gap G ₁ (P ₂ / P ₁₎
Is set in the range of 1.5 to 2.1.

With this configuration, two air gaps are provided.
Top G₁, G_TwoActs on movable valve by magnetic circuit with
The permeance ratio of a solenoid valve that generates electromagnetic attraction
(P _Two/ P₁) Is in the range of 1.5 to 2.1,
Each air gap G₁, G_TwoPermeance P in₁, P_Two
The valve operating voltage can be reduced by selecting
Moreover, the generation efficiency of the electromagnetic attraction force can be improved.
This allows the operation of the movable valve while miniaturizing the solenoid valve.
Responsiveness can be improved.

[0009] The invention of claim 2, the air gap G ₀ between the magnetic path forming member and the movable valve in a direction intersecting the direction of action of the electromagnetic attractive force is formed for the movable valve, permeance in the air gap G ₀ the P ₀ air gap G
Permeance ratio obtained by dividing the permeance P ₁ in ₁ (P
The ₀ / P _1), a solenoid valve according to claim 1, wherein set in the range of 0.55 to 0.9. With this configuration, as the permeance ratio (P ₀ / P ₁₎ is in the range of from 0.55 to 0.9, by selecting the permeance P _1, P ₀ in the air gap G _1, G ₀ In addition, the generation efficiency of the electromagnetic attraction force can be further improved while the valve operating voltage is further reduced.

A third aspect of the present invention is a fuel injection valve in which the movable valve in the solenoid valve according to the first or second aspect is supported by a leaf spring so as to be opened and closed. With this configuration,
The generation efficiency of the electromagnetic attraction force can be improved while the valve operating voltage for the movable body is reduced, and therefore, it is effective for a fuel injection valve that is small and requires high operation responsiveness of the movable valve.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. In this embodiment, a fuel injection valve using a gaseous fuel such as a compressed natural gas fuel will be exemplified. In FIG. 1 showing a cross-sectional view of a fuel injection valve, a substantially cylindrical body 1 is made of a magnetic material, and has an annular flange portion 1a protruding from an inner periphery of a central portion thereof. A substantially cylindrical core 2 is inserted into the rear half (the right half in FIG. 1) of the body 1. The core 2 is made of a magnetic material and has an annular flange portion 2a protruding from the outer periphery of the central portion. The core 2 is fixed to the body 1 by caulking the rear end of the body 1 to the flange portion 2a.

A substantially cylindrical bobbin 3 is arranged between the body 1 and the core 2. The bobbin 3 is made of an electrical insulating material such as a synthetic resin, and has the solenoid coil 4 wound in a multilayer shape. A terminal 5 projecting rearward is electrically connected to the solenoid coil 4. The terminal 5 penetrates the flange 2 a of the core 2.
The bobbin 3 and the body 1 are provided around the front end of the bobbin 3.
O-ring 6 in the form of a ring for sealing between
Is attached. A ring-shaped rear O-ring 7 that seals between the bobbin 3 and the core 2 is attached to the inner periphery of the rear end of the bobbin 3.

A power receiving connector 8 is formed on the outer periphery of the rear half of the core 2 by resin molding. The power receiving connector 8 has a socket portion 8 a surrounding the periphery of the terminal 5. Note that a power supply connector of an electronic control device (not shown) is connected to the socket portion 8a. As a result, a signal from the electronic control unit is input to the solenoid coil 4 through the terminal 5 to energize and release the solenoid coil 4.

A stopper 10, a collar 12, a leaf spring 16 with a movable valve 14, a ring 18, and a seat 20 are sequentially incorporated in the front half (the left half in FIG. 1) of the body 1. For convenience of explanation, sheet 20, stopper 1
0, collar 12, ring 18, movable valve 14, leaf spring 16
Will be described in this order.

First, the seat 20 is made of, for example, a stainless steel material, and a seat surface 22 is formed on a rear end surface thereof. A fuel injection port 21 is formed at the axial center of the seat 20.
The fuel injection port 21 has a tapered hole 21a having a smaller diameter from the rear end face toward the front, a small diameter hole 21b continuous with the front end of the tapered hole 21a, and a stepped surface ( Large-diameter hole portion 2 continuous through reference numeral omitted)
1c.

By caulking the front end of the body 1 to a stepped portion formed on the outer peripheral surface of the sheet 20,
The seat 20 is fixed to the body 1. This allows
A stopper 1 is provided between the flange 1a and the sheet 20.
0, collar 12, outer peripheral portion of leaf spring 16 and ring 18
Is pinched. Note that a ring-shaped sealing member 23 for sealing between the sheet 20 and the body 1 is attached to the outer periphery of the central portion of the sheet 20.

Next, the stopper 10 is formed in a ring plate shape from an electromagnetic stainless steel material which is a magnetic material, is fitted in the body 1, and is in contact with the flange portion 1a. FIG. 2 is an enlarged view of a main part of FIG.

Next, the collar 12 is formed in a ring shape from, for example, a stainless steel material, is fitted in the body 1, and is in contact with the outer peripheral portion of the stopper 10.

Next, the ring 18 is formed in a ring shape from, for example, stainless steel, is fitted in the body 1, and is in contact with the outer peripheral edge of the leaf spring 16. Ring 1
8 presses the outer peripheral edge of the leaf spring 16 against the collar 12 by fixing the seat 20 to the body 1. Thus, the outer peripheral edge of the leaf spring 16 is held between the collar 12 and the ring 18.

In FIG. 2, the movable valve 14 is made of an electromagnetic stainless steel material, which is a magnetic material, and has a cylindrical main part 14a having a cross section substantially similar to that of the core 2;
The main portion 14a has a flange portion 14b protruding from the outer periphery of the front portion and a disk-shaped valve portion 14c protruding from the front end portion of the main portion 14a. The main portion 14a and the flange portion 14b function as an armature when the solenoid coil 4 is energized.

A spring seat surface 14e, which is a stepped surface, is formed on the inner peripheral surface of the hollow portion (designated by reference numeral 14d) of the main portion 14a. The rear surface of the flange portion 14b is a contact surface 14f capable of making surface contact with the stopper 10.

The front surface of the valve portion 14c is a contact surface 14h capable of making surface contact with the seat surface 22 of the seat 20. Annular groove formed on the contact surface 14h (reference numeral omitted)
Is fitted with an annular damper member 15 having elasticity. When the movable valve 14 is closed, the damper member 15 comes into contact with the seat surface 22 of the seat 20 to perform a damper function and a sealing function.

The main portion 14a is provided in the valve portion 14c.
For example, four through holes 14k communicating with the hollow portion 14d and radially extending in the radial direction are formed. The hollow portion 14d and the through hole 14k form a fuel passage (reference numeral omitted) for the movable valve 14.

Next, the leaf spring 16 will be described. Leaf spring 16
3 is shown in FIG. 3, and FIG. 4 is a sectional view taken along line IV-IV of FIG. The leaf spring 16 is formed in a substantially disk shape, and is formed in a state where three long holes 16a along two inner and outer circumferential lines are shifted from each other by about 1/2 pitch. A concave portion 16b located between the other long holes 16a is formed in an intermediate portion of each long hole 16a. The leaf spring 16 is made of a material having a high fatigue limit, for example, SUS631,
It is formed of precipitation hardening stainless steel such as SUS632J1.

At the inner peripheral edge of the leaf spring 16, an elastic body 25 which covers the front and back surfaces and covers the edge is provided by insert molding. An appropriate number (six in FIG. 3) of holes 16c are formed at substantially equal intervals in the inner peripheral portion of the leaf spring 16, and front and back elastic members 25 are connected through the holes 16c. FIG. 5 is a partially enlarged view of a portion V in FIG. The elastic body 25 is formed of an elastic material having a good low-temperature property, for example, a perfluoro-based fluorine rubber, a perfluoroether-based fluorine rubber, a fluorosilicone rubber, or hydrogenated NBR.

Further, as shown in FIG.
The inner diameter D1 of the hole 25a is determined by the movable valve 14 (see FIG. 2).
Is set smaller than the outer diameter D2 of the main portion 14a.
Thereby, the elastic body 2 with respect to the main portion 14a of the movable valve 14
An interference T of 5 is set. Then, the valve portion 14c of the movable valve 14 is inserted into the hole 25a of the elastic body 25, and the movable valve 14 is attached to the elastic body 25 by interference fit with the interference T (see FIG. 3). The elastic body 25 is provided on the flange 14 of the movable valve 14.
b.

The outer peripheral edge of the leaf spring 16 is sandwiched between the collar 12 and the ring 18 as described above. Therefore, the movable valve 14 is supported by the leaf spring 16 so that it can be opened and closed in the axial direction. The movable valve 14 is opened by retreating from the closed state (moving rightward in FIG. 1), and is closed by moving forward (moving leftward in FIG. 1) from the open state. When the valve is closed, the valve portion 14c of the movable valve 14 is
Surface contact with 2. When the valve is opened, the movable valve 14
Is in surface contact with the stopper 10. The movable valve 14 is always kept closed by the elasticity of a coil spring 26 described later.

As shown in FIG. 1, a coil spring 26 is inserted into the core 2 from the rear thereof.
A pipe 27 for adjusting a spring load is inserted. The tip surface of the coil spring 26 is the spring seat surface 14 of the movable valve 14.
e (see FIG. 2). Also, the coil spring 26
The tip end face of the pipe 27 is in contact with the rear end face. The coil spring 26 always biases the movable valve 14 to a closed state. The pipe 27 is fixed to the core 2 by caulking after adjusting the spring load of the coil spring 26 with respect to the movable valve 14 by adjusting the insertion position.

Between the rear end face of the core 2 (right end face in FIG. 1) and the front end face of the seat 20, a hollow portion in the core 2 and the pipe 27, a hollow portion 14d of the movable valve 14, a through hole 14k, A series of fuel passages 29 composed of the fuel injection ports 21 of the seat 20 are formed. Note that a strainer 30 is incorporated at the rear end of the core 2.

An O-ring 31 is fitted in a concave groove (symbol omitted) formed on the outer periphery of the rear end of the core 2. The O-ring 31 seals between the core 2 and a delivery pipe (not shown) communicating therewith. A grommet 32 is fitted to the core 2 and contacts the rear end surface of the power receiving connector 8. The grommet 32 functions as a buffer between the power receiving connector 8 and the delivery pipe.

Next, the operation of the fuel injection valve configured as described above will be described. Fuel supplied under a predetermined pressure from a fuel tank (not shown) through a pressure regulating valve is filtered by a strainer 30, passes through a series of fuel passages 29, and closes the movable valve 14 with respect to the seat 20. To the part. Since the movable valve 14 is kept closed by the combined force of the spring loads of the leaf spring 16 and the coil spring 26, no fuel is injected.

Here, when the solenoid coil 4 is turned on by the input of an electric signal from the electronic control unit, a magnetic circuit M passing through the body 1, the core 2, the movable valve 14, and the stopper 10 (see a dotted line M in FIG. 1). The movable valve 14 is opened by being retracted by the electromagnetic attraction force due to the configuration of (1). When the movable valve 14 opens, fuel is injected from the fuel injection port 21 of the seat 20.

When the electric signal to the solenoid coil 4 is turned off and the electromagnetic attraction force acting on the movable valve 14 is eliminated, the movable valve 14 is closed as described above, Fuel injection stops.

In the above-mentioned fuel injection valve, an electromagnetic attraction force acting on the movable valve 14 by energizing the solenoid coil 4 is generated by a magnetic circuit M having two air gaps. That is, in the cross-sectional view of FIG. 6, one of the two air gaps G ₁ is
Core 2 around which solenoid coil 4 is wound and movable valve 14
Is formed between the main portion 14a and the main portion 14a. The core 2 corresponds to a “magnetic path forming member inside the solenoid coil 4” in the present invention.

The other air gap G_TwoIs
Formed between the housing 10 and the flange portion 14b of the movable valve 14.
It is. The stopper 10 is referred to as “air gap” in the present invention.
G ₁Outside of the magnetic path forming member ".

Further, between the main portion 14a of the magnetic circuit flange portion 1a and the movable valve 14 of the stopper 10 and the body 1 in the direction intersecting the M is the air gap G ₀ is formed. The stopper 10 and the flange portion 1a of the body 1 correspond to the "magnetic path forming member in the direction intersecting the direction of action of the electromagnetic attraction force on the movable valve" in the present invention.

In FIG. 7 showing an illustration of the air gap G ₁ , the facing distance between the facing surface of the core 2 and the main portion 14 a of the movable valve 14 is L ₁ , and the chamfering and the R surface of the facing surface are included. free sectional opposing width is W _1. A substantially donut-shaped area having a cross-section facing width W ₁ is the main part 1 of the core 2 and the movable valve 14.
4a the opposing area S ₁ (not shown) between. The permeance P ₁ in the air gap G ₁ is, P ₁ = (mu ₁
- represented by the S ₁₎ / L _1. Μ ₁ is the magnetic permeability in the air gap G ₁ . The counter distance L ₁ is a dimension in the time of closing of the movable valve 14.

In FIG. 8, which is a cross-sectional view of the periphery of the air gap G ₂ , the facing distance between the stopper 10 and the flange portion 14 b of the movable valve 14 is L ₂ , and the chamfer on the facing surface is L ₂ . The cross-section facing width not including
_{Assume 2} . Area of approximately donut shape of the cross section facing the width W ₂ is facing area S ₂ (not shown) between the flange portion 14b of the stopper 10 and the movable valve 14. And the air gap G ₂
Permeance P ₂ in is represented by _{P 2 = (μ 2 · S} 2) / L 2. Here, μ ₂ is the magnetic permeability in the air gap G ₂ . The counter distance L ₂ is the dimension at the time of closing of the movable valve 14.

Further, in FIG. 9 showing the periphery of the air gap G ₀ in cross-section, opposing between the opposing surfaces of the radial direction between the main portion 14a of the flange portion 1a and the movable valve 14 of the stopper 10 and the body 1 The distance is L ₀ , and the width of the opposing cross section in the axial direction not including the chamfer of the end of the surface and the R surface is W ₀ . In addition, in order to make the diameter of the donut shape the average diameter,
The cross-section facing width W ₀ is set at a position where the facing distance is の of L ₀ .

The substantially cylindrical area of the cross-section facing width W ₀ is the radial facing area S ₀ (not shown) between the stopper 10 and the flange portion 1 a of the body 1 and the main portion 14 a of the movable valve 14. The permeance P ₀ in the air gap G ₀ is expressed by _{P 0 = (μ 0 · S} 0) / L 0. Μ ₀ is the magnetic permeability in the air gap G ₀ .

[0041] Thus, the larger the facing area S ₂ of the flange portion 14b of the stopper 10 and the movable valve 14 in the air gap G _2, the greater the permeance P _2, it is possible to increase the electromagnetic attraction force. However, since the physical size of the fuel injection valve is limited, the radius R (see FIG. 6) from the axis of the body 1 to the inner peripheral surface of the portion where the stopper 10, the collar 12, and the like fits is generally almost equal. It is considered to be constant size. Therefore, when too large facing area S ₂ in the air gap G ₂ by the increase in the outer diameter of the flange portion 14b of the movable valve 14, the body 1 and the movable valve 14
(See FIG. 8) facing the distance L in the radial direction of the flange portion 14b is reduced, (in FIG. 6, the two-dot chain line M ₁ reference) flux leakage M ₁ here increases result, magnetic attraction decreases I do.

Further, if too large facing area S ₂ in the air gap G ₂ by a reduction of the inner diameter of the stopper 10, the opposing distance in the air gap G ₀ L ₀ (FIG. 9
) Becomes small, and the leakage magnetic flux M ₀ here (see FIG. 6,
The two-dot chain line M ₀ reference) increases result, this also the electromagnetic attractive force is reduced.

[0043] Also, the larger the facing distance L ₀ in the air gap G _0, the leakage magnetic flux M ₀ here decreases. Then, the magnetic flux flowing through the air gap G ₁ and the air gap G ₂ increases, and the permeances P ₁ and P ₂
, The electromagnetic attraction increases. However, if too large opposing distance L _0, the facing area S ₂ in the air gap G ₂ is less than optimum. Further, in order to increase the facing area S ₂ in the air gap G ₂ is,
The opposing distance L ₀ or the opposing distance L in the air gap G ₀ is reduced, and the leakage magnetic fluxes M ₀ and M ₁ are increased here. As a result, the electromagnetic attractive force is reduced.

Therefore, the applicant of the present application has proposed a radial opposing distance L between the body 1 and the flange portion 14b of the movable valve 14 (FIG. 8).
), The facing distances L ₁ , L ₂ , L ₀ and the cross-sectional facing widths W ₁ , W ₂ , W _0, etc.
After preparing samples having different permeances P ₁ , P ₂ , and P ₀ , the valve operating voltage was measured.

[0045] Then, based on the measurement result, the air gap G ₁ permeance P ₂ in the air gap G ₂
Permeance ratio divided by permeance P ₁ at (P ₂
/ P ₁ ), the change in the valve operating voltage was confirmed by making a graph as shown in FIG.

In FIG. 10, the horizontal axis is the permeance ratio (P ₂ / P ₁ ), and the vertical axis is the valve operating voltage. In this case, the permeance ratio obtained by dividing the permeance P ₁ the permeance P ₀ in the air gap G ₀ in the air gap G ₁ (P ₀ / P ₁₎ was 0.7. As is clear from FIG. 10, the permeance ratio (P ₂ / P ₁ ) is 1.5 to
By setting the value in the range of 2.1, the valve operating voltage can be reduced. Incidentally, 1.5 Considering the dimensional tolerances of the components, permeance ratio (P ₂ / P ₁₎
In particular, by setting the permeance ratio (P ₂ / P ₁ ) to 1.8,
The valve operating voltage can be minimized.

Further, based on the measurement result, the permeance ratio obtained by dividing the permeance P ₀ in the air gap G ₀ by permeance P ₁ in the air gap G ₁ (P ₀ /
How the valve operating voltage changes due to P ₁ ) was confirmed by graphing as shown in FIG.

In FIG. 11, the horizontal axis is the permeance ratio (P ₀ / P ₁ ), and the vertical axis is the valve operating voltage. In this case, the permeance ratio obtained by dividing the permeance P ₁ the permeance P ₂ in the air gap G ₂ in the air gap G ₁ (P ₂ / P ₁₎ was 1.8. As is clear from FIG. 11, the permeance ratio (P ₀ / P ₁ ) is set to 0.5.
By setting the value in the range of 5 to 0.9, the valve operating voltage can be reduced. In consideration of the dimensional tolerance of the component parts, the permeance ratio (P ₀ / P ₁ ) is set to 0.
The valve operating voltage can be set to a value within the range of 55 to 0.9. In particular, by setting the permeance ratio (P ₀ / P ₁ ) to 0.7, the valve operating voltage can be minimized.

According to the above-described fuel injection valve, the magnetic circuit M that generates an electromagnetic attraction force acting on the movable valve 14 when the solenoid coil 4 is energized includes the core 2 inside the solenoid coil 4 and the movable valve 14. an air gap G ₁ is formed between, has an air gap 2 places the air gap G ₂ is formed between the stopper 10 in the outside of the air gap G ₁ and the movable valve 14, the permeance ratio obtained by dividing the permeance P ₁ the permeance P ₂ in the air gap G ₂ in the air gap G ₁ and (P ₂ / P _1), it is obtained by setting the range of 1.5 to 2.1. Therefore, the permeance ratio (P ₂ /
By selecting the permeances P ₁ and P ₂ in each of the air gaps G ₁ and G ₂ so that P ₁ ) falls within the range of 1.5 to 2.1, the operating voltage required for the operation of the movable valve 14 is reduced. The generation efficiency of the electromagnetic attraction force can be improved while reducing the size. As a result, while reducing the size of the solenoid valve,
The operation responsiveness of the movable valve 14 can be improved.

[0050] Further, the air gap G ₀ between the main portion 14a of the flange portion 1a and the movable valve 14 of the stopper 10 and the body 1 in a direction intersecting the direction of action of the electromagnetic attractive force is formed for the movable valve 14, the permeance ratio obtained by dividing the permeance P ₁ the permeance P ₀ in the air gap G ₀ in the air gap G ₁ a (P ₀ / P _1),
It is set in the range of 0.55 to 0.9. Accordingly, permeance ratio (P ₀ / P ₁₎ is from 0.55 to 0.
By selecting the permeances P ₁ and P ₀ in the air gaps G ₁ and G ₀ so as to fall within the range of 9, the operating voltage required to operate the movable valve 14 can be further reduced.
The generation efficiency of the electromagnetic attraction can be further improved.

The movable valve 14 is a fuel injection valve supported by a leaf spring 16 so as to be openable and closable.
While the operating voltage required for the operation of Step 4 is reduced, the generation efficiency of the electromagnetic attraction force can be improved, and therefore, it is effective for a fuel injection valve that is small and requires high operation responsiveness of the movable valve 14.

The present invention is not limited to the above embodiment, but can be modified without departing from the spirit of the present invention. For example, the movable valve 14 is an integrally molded product having the main portion 14a, the flange portion 14b, and the valve portion 14c. However, the movable valve 14 may be configured by combining components in which the respective portions 14a, 14b, 14c are formed separately. The fuel used for the fuel injection valve is preferably compressed natural gas, but is not limited to the use of other fuels such as gasoline and liquefied gas. Further, the present invention is not limited to the fuel injection valve, but can be applied to various solenoid valves.

[0053]

According to the fuel injection valve of the present invention, the electromagnetic attraction force acting on the movable valve is generated by a magnetic circuit having two air gaps. By improving the force generation efficiency, it is possible to reduce the size and improve the operation responsiveness of the movable valve.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a fuel injection valve showing one embodiment.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a front view of a leaf spring.

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3;

FIG. 5 is a partially enlarged view of a portion V in FIG. 4;

FIG. 6 is a cross-sectional view illustrating an air gap.

7 is a sectional view showing the periphery of the air gap G _1.

8 is a sectional view showing the periphery of the air gap G _2.

9 is a sectional view showing the periphery of the air gap G _0.

FIG. 10 is a characteristic diagram showing a relationship between a permeance ratio (P ₂ / P ₁ ) and a valve operating voltage.

FIG. 11 is a characteristic diagram showing a relationship between a permeance ratio (P ₀ / P ₁ ) and a valve operating voltage.

[Explanation of symbols]

1 body (magnetic path forming member) 2 core (magnetic path forming member) 4 Solenoid coil 10 stops (magnetic path forming member) 14 movable valve 16 the leaf spring G ₁ air gap G ₂ air gap G ₀ air gap M magnetic circuit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Koji Kawazoe 1-1-1, Kyowa-cho, Obu City, Aichi Prefecture Inside Ai San Industry Co., Ltd. (72) Inventor Toshiro Makimura 1-1-1, Kyowa-cho, Obu City, Aichi Prefecture 1 Ai San Industry Co., Ltd. F term (reference) 3G066 AA01 AB02 AB05 BA19 BA67 CB05 CC51 CE23 CE24 CE25 CE26 CE31 3H106 DA07 DA13 DA23 DB02 DB12 DB23 DB32 DC02 DC17 DD03 EE16 GA24 GC20 KK18

Claims (3)

[Claims] A magnetic circuit for generating an electromagnetic attraction force acting on a movable valve by energizing a solenoid coil includes an air gap G formed between a magnetic path forming member inside the solenoid coil and the movable valve. the electromagnetic valve with _1, and the air gap G ₂ is formed between the magnetic path forming member and the movable valve in the outside of the air gap G _1, an air gap of two locations, the air gap G ₂ solenoid valve permeance ratio obtained by dividing the permeance P ₁ the permeance P ₂ in the air gap G ₁ and (P ₂ / P _1), it was set in the range of 1.5 to 2.1 at. Wherein an air gap G ₀ between the magnetic path forming member and the movable valve in a direction intersecting the direction of action of the electromagnetic attractive force for the movable valve is formed, the air gap permeance P ₀ in the air gap G ₀ permeance ratio obtained by dividing the permeance P ₁ in G ₁ a _{(P 0 / P 1),} 0.
The solenoid valve according to claim 1, wherein the solenoid valve is set within a range of 55 to 0.9. 3. A fuel injection valve according to claim 1, wherein the movable valve is supported by a leaf spring so as to be opened and closed.