JPH01138365A - Electromagnetic type fuel injection valve for internal combustion engine - Google Patents

Abstract

PURPOSE:To improve the operation responsiveness by forming a valve member from the nonmetallic material having a specific value of specific gravity and forming a hardened layer on the surface, in the constitution in which the valve member which is moved in reciprocation by an electromagnetic actuator is installed in a valve body. CONSTITUTION:In a valve body 11 assembled at the top edge part of a valve case having an electromagnetic actuator built in, a slender needle-shaped valve member 20 having two slidable parts 21 and 22 is fitted in slidable ways into a guide hole 17, and said valve member 20 opens and closes an injection hole 14 by attaching and separating the contact part 23 for a valve seat 16. In this case, the valve member 20 is made of the nonmetallic material having a specific gravity of 5 or less as basic material, e.g., aluminum alloy (specific gravity of 2.7), and a hardened layer 61 made of titanium nitride is formed on the surface. In this case, a tapered part 62 is formed at the positions corresponding to the slidable parts 21 and 22 of the valve member 20, and after the hardening treatment, the tapered part 62 is grinding-worked so that the outer periphery is made parallel to a guide hole 17, and the gap (alpha) is adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electromagnetic fuel injection valve for supplying fuel to an internal combustion engine.

[Prior Art] As shown in Fig. 1, conventional electromagnetic fuel injection valves are as follows:
The valve body 11 includes a valve body 11 in which an injection hole 14 and a valve seat 16 are formed, and a valve member 20 that has a contact portion 23 that abuts the valve seat 16 and is movably disposed within the valve body 11. . The valve member 20 has an armature 36 connected to one end thereof,
The electromagnetic actuator 35 causes the contact portion 2 of the valve member 20 to
3 contacts the valve seat 16 and stops supplying fuel to the internal combustion engine; and an open position where the contact portion 23 is separated from the valve seat 16 and allows supply of fuel to the internal combustion engine. It is designed to be driven back and forth. Further, the valve member 20 is made of a steel material that can be quenched and hardened, and the armature 36
is made of magnetic material.

(Problem to be solved by the invention) However, in such a configuration, the specific gravity of the rope is 7.9.
-8.1, which caused the problem that the operational responsiveness of the valve member 20 was not sufficient for the responsiveness required by the internal combustion engine. Furthermore, the operational response can be improved by using a material with low specific gravity for the valve member 20, but since the valve member 20 repeatedly collides between the valve seat 16 and the stopper 31, sufficient wear resistance is required. toughness and toughness are required;
As a result, there was a problem in that it was necessary to use steel materials that could be quenched and hardened.

The present invention was made in view of the above problems.
An electromagnetic fuel injection valve equipped with a valve member that has sufficient responsiveness to drive by an electromagnetic actuator and has sufficient wear resistance and toughness to withstand collisions with the valve seat or stopper. The purpose is to provide.

[Means for solving problems]

In order to solve the above problems, the following technical measures were taken.

That is, the valve member driven by the electromagnetic actuator is formed of a non-ferrous metal material with a specific gravity of 5 or less,
A hardened layer was formed on the surface.

Examples of non-ferrous metal materials having a specific gravity of 5 or less include aluminum and its alloys, magnesium and its alloys, titanium and its alloys, and the like.

Further, the hardened layer formed on the surface of the valve member includes titanium nitrides and carbides, or nitrides, carbides, and oxides of the same material as the nonferrous metal material forming the valve member.

〔Example〕

An embodiment of the present invention will be described below based on the drawings.

The electromagnetic fuel injection valve 1 shown in FIG. It is integrally connected to the valve case 12.

A case cover 13 is attached to the valve body 11 by press fitting. Further, the valve body 11 is provided with an injection hole 14 for injecting fuel into the cylinder or an intake pipe, and a valve seat 16 formed continuously with the injection hole 14.

A guide hole 17 is formed in the valve body 11, and the guide hole 17
The elongated needle-type valve member 20 housed in is provided with two sliding parts 2 and 22, and these sliding parts 21
and 22 are fitted to the wall surface of the guide hole 17 with a gap of several μm in order to allow the valve member 20 to slide smoothly.

The valve member 20 has a contact portion 23 provided on the valve member 20.
The contact portion 23 contacts the valve seat 16 to close the injection hole 14 and stop supplying fuel to the internal combustion engine.
The valve body 1 is disposed in a guide hole 17 so as to be movable with respect to the valve body 1 between an open position in which the injection hole 14 is spaced apart from the valve body 1 and an injection hole 14 is opened, allowing fuel to be supplied to the internal combustion engine.

A disk-shaped stopper 31 is interposed and fixed between the rear end of the valve member 20 and the valve case 12, and when the flange 32 provided on the valve member 20 comes into contact with the stopper 31, the valve member 20 is moved to the open position. is now determined. The rear end portion of the valve member 20 passes through the stopper 31 and extends into the valve case 12.

An electromagnetic actuator 35 is disposed within the valve case 12 to drive the valve member 20 to move the valve member 20 between a closed position and an open position. The electromagnetic actuator 35 is in a fixed relationship with an actuator 36 connected to the rear end of the valve member 20 with respect to the valve case 12,
It therefore has a stator 37 mounted in fixed relation to the valve body 20 and an electromagnetic coil 38 wound around the stator 37. armature 36
is urged toward the closed position by the return coil spring 39, that is, downward in FIG. The valve member 20 is attracted toward the stator 37 against the biasing force of the coil spring 39, and the flange 32 comes into contact with the stopper 31, so that the valve member 20 assumes the open position.

When the supply of current to the electromagnetic coil 38 is stopped, the valve member 2
0 is the stator 37 due to the urging force of the return coil spring 39.
When the valve member 20 moves in a direction away from the valve member 20 and the abutting portion 23 of the valve member 20 abuts the valve seat 16, the valve member 20 assumes the closed position. The electromagnetic coil 38 is connected to an electronic control circuit (not shown) including a microcomputer via a terminal 41, and the electronic control circuit controls supply and termination of current to the electromagnetic coil 38.

The stator 37 is integrally provided with a flange 43, which is fixedly attached to the rear end of the valve case 12. A joint portion 4 connected to the branch pipe 8 from the end face of the flange 43 on the opposite side to the stator 37
4 extend integrally, and a filter 46 is disposed within the joint portion 44, and an adjusting pipe 47 for adjusting the biasing force of the return coil spring 39 is disposed. The upstream end of the internal passage 48 of the adjusting pipe 47 is connected to the joint portion 44.
The downstream end is connected to the branch pipe 8 through the central hole 49 formed in the armature 36, the outer circumference of the armature 36, the flat surface portion 51 of the valve member 20, the central hole 52 of the stopper 31, and the downstream end thereof. , and communicates with the injection hole 14 via a fuel passage 53 between the valve member 20 and the wall surface of the guide hole 17 .

In the above configuration, as shown in FIGS. 2 and 3, the valve member 20 has an aluminum alloy (specific gravity 2
．． 7) is used, and a hardened layer 61 of nitrogen titanium is further formed on its surface.

Next, a specific method of manufacturing the valve member 20 will be described.

First, the base material 60 of the valve member 20 is processed into a predetermined shape from an aluminum alloy.
As shown in FIG. 4, an oceanic tapered portion 62 is formed at the portions corresponding to 1 and 22. As shown in FIG.

Then, a hardened layer 61 of titanium nitrogen is formed on the surface of the valve member 20 by a conventionally known method. At this time, since strain occurs in the base material 60 of the valve member 20 due to the hardening process,
The machining allowance of the hardened titanium nitride 7161 is not constant.

As a result, the gap α of several μm between the valve member 20 and the guide hole 17 of the valve body 11 deviates. Therefore, in this example,
As described above, the tapered portion 62 is formed at the portion of the valve member 20 corresponding to the sliding portions 21 and 22, and after hardening treatment, the tapered portion 62 is hardened so that the outer periphery thereof is parallel to the guide hole 17 as shown in FIG. The gap α is adjusted by grinding.

Next, the operation of this embodiment will be explained.

In the electromagnetic fuel injection valve 1 shown in FIG. 1, when no current is supplied to the electromagnetic coil 38 from the electronic control circuit (not shown) via the terminal 41, the processed fuel supplied to the joint 44 is transferred to the filter 46. , passes through the inner passage of the adjusting pipe 47, passes through the center hole 49 formed in the armature 36, the outer circumference of the armature 36, the flat surface portion 51 of the valve member 20, and the center hole 52 of the stopper 31, and passes through the valve member 20. and the wall surface of the guide hole 17, but in this case, the valve member 20 is in the closed position with the contact portion 23 seated on the valve seat 16 by the return coil spring 39. Therefore, fuel is not injected to the outside from the fuel injection hole 13.

On the other hand, when current is supplied from an electronic control circuit (not shown) to the electromagnetic coil 3 through the terminal 41, the valve member 20
The stator 37 resists the biasing force of the return coil spring 39.
The flange 32 moves until it comes into contact with the stopper 31 and assumes the open position. Therefore, the fuel supplied to the joint part 44 is transferred to the filter 46, the internal passage 48 of the adjusting pipe 47, and the center hole 49 of the armature 36.
, flat surface portion 51 of valve member 20, center hole 5 of stopper 31
2. The fuel is injected into the cylinder or intake pipe through the fuel passage 53 and the fuel injection hole 14. When a current is supplied to the terminal 41 from an electronic control circuit (not shown) in this manner, the valve member 20 is attracted by the stator 37 and opens, so that fuel injection is performed in accordance with the application time of the current.

Here, the operating speed of the electromagnetic fuel injection valve 1 is determined by the current value required for the valve member 20 to open after voltage is applied;
That is, it is determined by the time t1 required to reach the lowest operating current value and the time t2 required for the valve member 20 to actually move. Therefore, under the condition that time t1 is constant,
In order to improve the operational responsiveness of the valve member 20, the time L2
It is necessary to make it smaller.

The time t2 required for this movement decreases in proportion to the 1/2 to 1/3 power of the mass m of the movable part (valve member 11 and armature 36), but the material of the armature 36 is ferromagnetic. As such, there are restrictions on the selection of materials with low specific gravity.

Therefore, in this embodiment, the valve member 20 is made of an aluminum alloy having a smaller specific gravity than conventional steel materials, thereby improving the operational response of the valve member 20.

Further, as the valve member 20 reciprocates, the contact portion 23 of the valve member 20 collides with the valve seat 16, but in this embodiment, a hardened layer 61 of titanium nitride is formed on the surface of the valve member 20. Therefore, no wear occurs due to collisions.

Furthermore, during the reciprocating operation of the valve member 20, the attraction force of the electromagnetic actuator 35 and the urging force of the return coil spring 39 act on the valve member 20, but this acting force does not necessarily act on the central axis of the valve member 2o. Instead, the valve member 2o operates while tilting at the tilt angle β, as shown in FIG. However, in this embodiment, as shown in FIG. 4, the sliding parts 20 and 21 are machined into a tapered shape and the surfaces are hardened, and then ground so that they are parallel to each other. Even during operation, a portion of the hardened layer 61 engages with the inner wall of the guide hole 17, as shown in FIGS. 2 and 3, so that the sliding parts 2o and 21 are not worn out.

In addition, as shown in FIG. 5, the hardened layer 61 may be formed with a plurality of grooves on the outer periphery of the sliding parts 20 and 21, and processed to be smooth after hardening treatment.

Furthermore, in this embodiment, since a titanium nitride layer is formed as the hardened layer 61 of the valve member 20, it is very hard and does not peel off from the base material 60, so it has high toughness and excellent wear resistance. This is an advantage.

The present invention is not limited to the embodiments described above, and can be modified in various ways without departing from the spirit thereof.

For example, the base material 61 of the valve member 20 may include, in addition to aluminum alloy, aluminum, magnesium or its alloy, which is a non-ferrous metal material with a specific gravity of 5 or less, titanium or its alloy. In addition to titanium nitride, surface hardening N62 includes titanium carbides, base material nitrides, carbides, and oxides.

[Effects of the Invention] As explained above, according to the present invention, the valve member has a specific gravity of 5
With the simple structure of forming the following non-ferrous metal material and forming a hardened layer on its surface, the operational response of the valve member is greatly improved, and the hardened layer prevents wear due to collisions of operation. .

[Brief explanation of the drawing]

1 to 4 relate to an embodiment of the present invention, in which FIG. 1 is a longitudinal sectional view showing the overall configuration, FIG. 2 is a sectional view showing the main parts of this embodiment, and FIG. 3 is an enlarged view of the part surrounded by ■ in Fig. 2, Fig. 4 is a sectional view for explaining the method of processing the sliding part of the valve member of this embodiment, and Fig. 5 is an enlarged view of another embodiment of the present invention. It is a partial sectional view showing an example. 1... Electromagnetic fuel injection valve, 11... Valve body, 14.
...Fuel injection hole, 21.22...Sliding part, 35...
Electromagnetic actuator, 60... Base material, 61... Surface hardening layer. Representative Patent Attorney Takashi Okabe Figure 1 β Volume 2 Figure 3 Figure 4 Figure 5

Claims (8)

[Claims] (1) An electromagnetic type for internal combustion engines in which a valve member movably disposed within a valve body having an injection hole is reciprocated by an electromagnetic actuator to open and close the injection hole to supply and stop fuel. An electromagnetic fuel injection valve for an internal combustion engine, characterized in that the valve member is made of a nonferrous metal material with a specific gravity of 5 or less, and a hardened layer is formed on the surface of the valve member. (2) Claim 1, wherein the non-ferrous metal material forming the valve member is an aluminum-based material.
An electromagnetic fuel injection valve for an internal combustion engine as described in . (3) Claim 1, wherein the non-ferrous metal material forming the valve member is a magnesium-based material.
An electromagnetic fuel injection valve for an internal combustion engine as described in . (4) The electromagnetic fuel injection valve for an internal combustion engine according to claim 1, wherein the non-ferrous metal material forming the valve member is a titanium-based material. (5) The electromagnetic fuel injection valve for an internal combustion engine according to claim 1, wherein the hardened layer formed on the surface of the valve member is titanium nitride or carbide. (6) The hardened layer formed on the surface of the valve member is any one of nitride, carbide, and oxide of the nonferrous metal material forming the valve member.
An electromagnetic fuel injection valve for an internal combustion engine as described in . (7) The valve member has a sliding part formed to maintain a predetermined gap with the valve body, and the sliding part is processed into a large diameter tapered shape, and after the hardened layer is formed, the sliding part is processed into a large diameter tapered shape. 2. The electromagnetic fuel injection valve for an internal combustion engine according to claim 1, wherein the outer peripheries are processed to be parallel to each other. (8) The valve member has a sliding part formed to maintain a predetermined gap with the valve body, and the sliding part has a plurality of grooves formed therein, and then the hardened layer is formed on the sliding part. An electromagnetic fuel injection valve for an internal combustion engine according to claim 1, characterized in that: