JP2000249022A - Fuel injection valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve operating durability by preventing abrasion of a movable valve and/or a plate spring, and preventing breakage of the plate spring, in a device wherein the movable valve of a fuel injection valve is supported freely to open/close by the plate spring. SOLUTION: A movable valve 14 is openly and closely supported by a plate spring 16. An elastic body 25 is disposed between the movable valve 14 and the plate spring 16. The movable valve 14 and the plate spring 16 are brought into metallically contact with each other, and thereby abrasion of the movable valve 14 and/or the plate spring 16 is prevented. The elastic body 25 is elastically deformed, and thereby stress applied from the movable valve 14 on the plate spring 16 is reduced, and the breakage of the plate spring 16 is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fuel injection valve mainly using a gaseous fuel such as a compressed natural gas fuel.

[0002]

2. Description of the Related Art In a conventional fuel injection valve of this kind, a movable valve is supported by a leaf spring so as to be openable and closable (for example, see Japanese Patent Application Laid-Open No. Hei 4-31662). However, the leaf spring was generally in metal contact with the movable valve.

[0003]

According to the conventional fuel injection valve, since the leaf spring is in metallic contact with the movable valve, the movable valve is opened and closed (including a "dancing operation" accompanying the opening and closing operation). Rubbing causes wear of the movable valve and / or the leaf spring, which tends to reduce the operation durability.

When the leaf spring is fixed to the movable valve in order to prevent the abrasion, the stress applied to the leaf spring by the opening and closing operation of the movable valve is large. This also reduces the operating durability.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a movable valve which can be opened and closed by a leaf spring. Another object of the present invention is to provide a fuel injection valve capable of improving operation durability by preventing abrasion of a leaf spring and preventing breakage of the leaf spring.

[0006]

According to a first aspect of the present invention, there is provided a fuel injection valve for supporting a movable valve so that the movable valve can be opened and closed by a leaf spring. It is a fuel injection valve provided with a body. With this configuration, the elastic body provided between the movable valve and the leaf spring prevents metal contact between the movable valve and the leaf spring, thereby preventing wear of the movable valve and / or the leaf spring. .
At the same time, the stress applied to the leaf spring from the movable valve is reduced by the elastic deformation of the elastic body, whereby breakage of the leaf spring can be prevented. Therefore, the operation durability can be improved by preventing wear of the movable valve and / or the leaf spring and preventing breakage of the leaf spring.

According to a second aspect of the present invention, there is provided the fuel injection valve according to the first aspect, wherein an elastic member is attached to the leaf spring, and a movable valve is fitted into a hole of the elastic member. With this configuration, the movable valve can be easily assembled to the leaf spring by tightly fitting the movable valve into the hole of the elastic body by utilizing the elastic deformation.

According to a third aspect of the present invention, there is provided the fuel injection valve according to the first or second aspect, wherein the elastic body is formed of an elastic material having a good low temperature property. With this configuration, it is possible to prevent the elastic body from hardening at a low temperature, and it is effective to prevent breakage of the leaf spring at a low temperature. More specifically, when the elastic body hardens at a low temperature, the stress applied to the leaf spring increases, and the leaf spring is easily broken. However, when the elastic body is an elastic material having a good low-temperature property, the hardening of the elastic body at a low temperature is prevented, so that an increase in stress applied to the leaf spring can be prevented,
Therefore, breakage of the leaf spring at low temperatures can be prevented.
The elastic material having a good low-temperature property is an elastic material described as having good, high, or excellent low-temperature properties according to known literature.

A fourth aspect of the present invention is the fuel injector according to any one of the first to third aspects, wherein the leaf spring is formed of a material having a high fatigue limit. With this configuration, the operation durability of the leaf spring itself can be improved, which is effective in preventing breakage of the leaf spring. Note that a material having a high fatigue limit is a material described as being high or excellent in the fatigue limit according to a known document or the like.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. 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.
have. 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 disposed 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 of 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
The stopper 10, the collar 12, the outer peripheral portion of the leaf spring 16 and the ring 18 are sandwiched between the flange 1a and the seat 20. 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 material, which is a magnetic material, fitted into the body 1 and abutted on 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 into a ring shape from, for example, a stainless steel material, 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. As a result, the outer peripheral edge of the leaf spring 16 is sandwiched 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 (indicated 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 which can make surface contact with the seat surface 22 of the seat 20. Annular groove formed in 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 connected to 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, a precipitation hardening stainless steel such as SUS631, SUS632J1 or the like.

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 made of an elastic material having a good low-temperature property, for example, a perfluoro fluororubber, a perfluoroether fluororubber, a fluorosilicone rubber, or hydrogenated NBR.

Further, as shown in FIG.
The inner diameter D1 of the hole 25a of the movable valve 14 is
It is set smaller than the outer diameter D2 (see FIG. 2).
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 inserted into the elastic body 25 as shown in FIG. 2 by an interference fit with the interference T (see FIG. 3).
Is attached. The elastic body 25 is a movable valve 14
Is in contact with the flange portion 14b.

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 surface of the core 2 (the right end surface in FIG. 1) and the front end surface 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 from a fuel tank (not shown) under a predetermined pressure via a fuel pressure regulating valve is filtered by a strainer 30 and then passes through a series of fuel passages 29 to move the movable valve 14 for the seat 20.
To the closing part of 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 path 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 retreating due to the electromagnetic action caused by the above configuration. 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 action acting on the movable valve 14 disappears, the movable valve 14 is closed as described above, whereby the fuel Injection stops.

According to the fuel injection valve described above, the movable valve 14
By avoiding metal contact between the movable valve 14 and the leaf spring 16 by the elastic body 25 provided between the
Wear of the movable valve 14 and / or the leaf spring 16 can be prevented. At the same time, the stress applied to the leaf spring 16 from the movable valve 14 by the elastic deformation of the elastic body 25 is reduced, so that breakage of the leaf spring 16 can be prevented. Therefore, by preventing wear of the movable valve 14 and / or the leaf spring 16 and preventing breakage of the leaf spring 16, operation durability can be improved.

The movable valve 14 is connected to the hole 25a of the elastic body 25.
By using the elastic deformation to fit tightly,
The movable valve 14 can be easily assembled to the leaf spring 16.

Further, since the elastic body 25 is formed of an elastic material having a good low-temperature property, the hardening of the elastic body 25 at a low temperature can be prevented, which is effective for preventing breakage of the leaf spring 16 at a low temperature. More specifically, when the elastic body 25 hardens at a low temperature, the stress applied to the leaf spring 16 increases, and the leaf spring 16
Are easily broken. However, when the elastic body 25 is an elastic material having a good low temperature property, the hardening of the elastic body 25 at a low temperature can be prevented, so that an increase in stress applied to the leaf spring 16 can be prevented. The breakage of the leaf spring 16 can be prevented.

Further, since the leaf spring 16 is formed of a material having a high fatigue limit, the operation durability of the leaf spring 16 itself can be improved, which is effective in preventing breakage of the leaf spring 16. When SUS631 or SUS632J1, which is a precipitation hardening stainless steel having a high fatigue limit, was used for the leaf spring 16, it was found that the austenitic stainless steel S
The breakage of the leaf spring 16 was able to be prevented for a long time as compared with the case where US301 was used.

The present invention is not limited to the above embodiment, but can be modified without departing from the scope of the present invention. For example, the elastic body 25 is desirably provided on the entire circumference, but may be provided intermittently in the circumferential direction. Further, the elastic body 25 may be attached to the movable valve 14 instead of the leaf spring 16. Although the movable valve 14 is an integrally molded product having the main portion 14a, the flange portion 14b, and the valve portion 14c, 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, in the above embodiment, the present invention is applied to the top feed type fuel injection valve, but it may be applied to the side feed type fuel injection valve. In the above embodiment,
Although the present invention is applied to the normally closed type, it is also possible to apply to the normally open type.

[0040]

According to the fuel injection valve of the present invention, the movable valve is supported by the leaf spring so as to be opened and closed, and the movable valve and / or the leaf spring is provided by the elastic body provided between the movable valve and the leaf spring. By preventing wear of the spring and preventing breakage of the leaf spring, operation durability can be improved.

[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;

[Explanation of symbols]

 14 Movable valve 16 Leaf spring 25 Elastic body

 ──────────────────────────────────────────────────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 AD10 BA31 BA46 BA49 CC06U CC16 CC51 CD04 CE22

Claims (4)

[Claims] 1. A fuel injection valve for supporting a movable valve to be opened and closed by a leaf spring, wherein an elastic body is provided between the movable valve and the leaf spring. 2. The fuel injection valve according to claim 1, wherein an elastic body is attached to the leaf spring, and a movable valve is fitted in a hole of the elastic body. 3. The fuel injection valve according to claim 1, wherein the elastic body is formed of an elastic material having a good low-temperature property. 4. The fuel injection valve according to claim 1, wherein the leaf spring is formed of a material having a high fatigue limit.