JPH04117174U - fuel injection valve - Google Patents

Abstract

(57) [Summary] [Purpose] To ensure the strength of the connection between the valve and the armature and the operational response of the valve, and to widen the passage area of the fuel passage to ensure the linearity of the flow rate characteristics over a wide range. [Structure] A substantially cylindrical armature 9 is fitted onto a shaft portion 8b of a valve 8. Two fuel grooves 9a are formed in the armature 9, parallel to the axial direction and symmetrical about the central axis.
The groove width A of the groove 9a is smaller than the shaft diameter B of the shaft portion 8b. A mounting portion 9b of the armature 9 is fixed to the shaft portion 8b by laser welding or the like. Depth C of the groove 9a for reducing the diameter of the shaft portion 8b
By making the fuel passage deep, the passage area of the fuel passage can be widened. In addition, due to the reduction in weight due to the smaller diameter of the shaft portion 8b, the valve 8
This reduces the inertia force and improves operational response. Furthermore, by narrowing the groove width A of the groove 9a, the joint area of the attachment part 9b increases, and by making the thickness of the attachment part 9b thinner due to the concave surface 9c, low output power is required for laser welding, etc., thereby suppressing the generation of welding spatter. The strength of the connection between the valve 8 and the armature 9 can be increased.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention is for fuel injection valves, specifically for internal combustion engines installed in automobile engines, etc. This invention relates to electromagnetic fuel injection valves.

0002

[Conventional technology]

This type of fuel injection valve has a valve with a substantially cylindrical armature fitted to the base end shaft. There is a type that has a fuel passage between the base end shaft portion and the armature ( For example, Japanese Utility Model Application Publication No. 61-175565, Japanese Patent Application Publication No. 63-259280, (Refer to Publication No. 183263/1983). When forming the fuel passage, the method described in Japanese Utility Model Application No. 61-175565 is is symmetrical to the proximal shaft portion 81b of the valve 81, as shown in the cross-sectional view in FIG. A two-sided notch 81c is provided, and this and the inner circumferential surface of the cylindrical armature 91 The space formed by ).

0003 Also, JP-A-63-259280 and JP-A-63-183263 In this case, as shown in the cross-sectional view in FIG. A plurality of fuel grooves 92a extending in the axial direction are provided, and the proximal shaft portion 8 of the valve 82 is connected to the fuel grooves 92a. The space formed by the outer peripheral surface of 2b is the fuel passage (hereinafter, this will be referred to as (referred to as next case 2).

0004

[Problem that the idea aims to solve]

The fuel passage between the valve and armature in this type of fuel injection valve is The passage area is as wide as possible to reduce fluid (fuel) pressure loss and improve performance during large flow rates. However, it is desirable to ensure linearity of flow characteristics. Therefore, in order to increase the passage area of the fuel passage, in the conventional example 1, the valve 8 If the width across flats E between the notch 81c of 1 is made smaller, the valve 81 and the armature 9 As the bonding area of 1 decreases, the coaxiality when installing the armature decreases, and the laser Bond strength between valve 81 and armature 91 by welding or electron beam welding, etc. decreases. In addition, in order to increase the joint area, the shaft diameter B of the base end shaft portion 81b is If the weight of the valve 81 is increased, the inertia force will increase as the weight of the valve 81 increases. The operational response of No. 1 is impaired.

[0005] Further, in the conventional example 2, the shaft diameter B of the base end shaft portion 82b of the valve 82 is reduced. At the same time, the wall thickness D of the armature 92 is increased, and the depth C of the fuel groove 92a is increased. As a result, the wall thickness D of the valve mounting portion 92b with respect to the base end shaft portion 82b increases. others For this purpose, the armature 92 is attached to the valve 82 by laser welding or electron beam welding. If the valve is stuck, a large amount of power is required to melt it all the way to the valve side, and a spa Valve 8 2 and the armature 92 decreases. For this reason, in the conventional examples 1 and 2, the strength of the connection between the valve and the armature is While ensuring high fuel efficiency and valve operational response, the fuel passage area is widened. It is difficult to ensure linearity of flow characteristics over a wide range.

[0006] Therefore, the present invention was devised to solve the above-mentioned problems. The purpose is to ensure the strength of the connection between the valve and armature and the operational response of the valve. In both cases, the passage area of the fuel passage is widened to ensure linearity of the flow rate characteristics over a wide range. The object of the present invention is to provide a fuel injection valve that can

[0007]

[Means to solve the problem]

The fuel injection valve of the present invention that solves the above problems has the following features: It has a valve in which a substantially cylindrical armature is fitted to the base end shaft, and the base end shaft and In a fuel injection valve in which a fuel passage is provided between the armature and the formed on the inner circumferential surface of the armature, parallel to its axial direction, and symmetrical about the central axis at least two grooves having a groove width smaller than the shaft diameter of the proximal shaft portion of the valve. fuel grooves, provided between the fuel grooves in the circumferential direction of the armature; It is fixed to the proximal shaft part of the tube by welding means such as laser welding and has a recess on its outer surface. a thin-walled mounting portion having a surface; It is equipped with

[0008]

[Effect]

According to the above means, the diameter of the base end shaft portion of the valve is reduced and the diameter of the armature is reduced. By increasing the depth of the fuel groove, the valve is made lighter and the fuel passage remains open. The road area can be widened. Further, the groove width of the fuel groove is formed to be smaller than the shaft diameter of the base end shaft portion. Therefore, the joint area of the armature to the valve is increased. Also the armature Because the mounting part of the valve is thinned by forming a concave surface, it is difficult to connect the valve and armature. Low power is required for fixing by welding means such as laser welding.

[0009]

【Example】

[Example 1] Regarding Example 1 of the present invention, FIG. 2 shows a cross-sectional view of the fuel injection valve, and I of FIG. This will be explained with reference to FIG. 1, which shows a sectional view taken along the line -I. In FIG. 1, the electromagnetic fuel injection valve is inserted through a partition wall 2a having a central communication hole. It has a cylindrical housing 2 made of a magnetic material and partitioned into two chambers. Ha The electromagnetic coil 3 and core 4 are housed in one chamber of the housing 2, and the valve is housed in the other chamber. The sheet 5 is accommodated via a stopper 6 inserted in contact with the partition wall 2a.

0010 The core 4 is a hollow cylindrical body made of a magnetic material in which a fuel passage 4a is formed in the axial direction. ing. A cylindrical bobbin 3a around which the electromagnetic coil 3 is wound is arranged around the outer periphery of the core 4. is fitted. The core 4 is attached to the housing 2 by a flange 4b at its center. It is fixed by caulking, and a connector 12 made of synthetic resin is integrally molded on the outside. . The open end of the core 4 (the right end in Fig. 2) has a hole in it to prevent foreign matter from entering the fuel. A strainer 11 is press-fitted and fixed.

[0011] The electromagnetic coil 3 is connected to a terminal 12a disposed within the connector 12. It is. An electromagnetic control signal is transmitted from an electronic control device (not shown) through this terminal 12a. A drive signal that excites the coil 3 is supplied. The valve seat 5 has a fuel injection hole 5a in a small diameter portion at its tip. valve An adapter 10 for distributing the injected fuel in two directions is provided at the tip of the seat 5. There is. This adapter 10 is caulked and fixed to the housing 2 together with the valve seat 5. It is.

0012 A guide hole 5b communicating with the fuel injection hole 5a is formed in the axial center of the valve seat 5. It is. Inside this guide hole 5b is a valve 8 having a conical valve body 8a at its tip. is inserted movably in the axial direction of the guide hole 5b. The amount of movement of valve 8 is It is regulated by the topper 6. Further, the valve 8 is, for example, the same as the valve of the conventional example 1. The large diameter portion is guided by the guide hole 5b, and the large diameter portion is guided by the guide hole 5b. It has an unusual shape and forms a fuel passage. Note that the valve body 8a is limited to a conical shape. It may be spherical or pintle type.

[0013] An armature 9 made of a substantially cylindrical magnetic material is fitted into the base end shaft portion 8b of the valve 8. It is worn. The mounting structure of the armature 9 to the valve 8 will be explained later. I will explain this in detail below. The proximal end surface of the valve 8 and the A compression spring 14 is connected between the core 4 and the end face of the pipe 13 fixed inside the core 4. It has been intervened. Therefore, the valve body 8a of the valve 8 is always held against the elastic force of the compression spring 14. It is pressed against the tapered inclined surface 5c of the valve seat 5 due to the force of The fuel injection hole 5a is kept closed.

[0014] Next, regarding the mounting structure of the armature 9 to the valve 8, in addition to FIG. This will be explained with reference to FIG. The base end shaft portion 8b of the valve 8 is a hollow cylindrical shaft. On the other hand, the armature 9 has a substantially front half (left half in FIG. 2) of the valve 8. It is fitted onto the proximal shaft portion 8b of the Even if the two fuel grooves 9a parallel to the direction and symmetrical about the central axis have a groove width A and a depth C, It is formed as follows. This groove width A is larger than the shaft diameter B of the base end shaft portion 8b of the valve 8. It is also formed small. This fuel groove 9a and the outer peripheral surface of the base end shaft portion 8b of the valve 8 The space formed by this is used as a fuel passage.

[0015] In addition, in FIG. 1, the two fuel grooves 9a in the circumferential direction of the armature 9 are Between them are two mounting parts 9b that are parallel to the axial direction and symmetrical about the central axis. . Each mounting portion 9b has a concave surface 9c in the form of a flat notch formed on its outer surface. It has a thin wall shape. Further, on the inner surface of each mounting portion 9b, there is provided a base for the valve 8. A circular arc surface 9d that can be fitted onto the end shaft portion 8b is formed. In addition, the abbreviation of armature 9 The inner diameter of the rear half (right half in FIG. 2) is the shaft diameter B of the base end shaft portion 8b of the valve 8. (see FIG. 1), and the wall surface of the hollow portion is the wall surface and slope of each fuel groove 9a. It is continuous with .

[0016] Further, the mounting portion 9b has a circular arc surface 9d inserted into the base end shaft portion 8b of the valve 8. In this state, laser melting using a well-known laser beam is applied from the outside in the radial direction of the armature 9. It is fixed by bonding. Note that electron beam welding is used instead of laser welding. You can also

[0017] In the fuel injection valve, a drive signal from an electronic control device (not shown) is sent to a terminal. When the voltage is applied from the core 12a to the electromagnetic coil 3, an electromagnetic force is applied between the core 4 and the armature 9. A suction force is generated, and the valve 8 connected to the armature 9 is compressed by the compression spring 14. It overcomes sexual power and is drawn to the core side. At this time, the amount of movement of valve 8 is determined by the stopper. It is regulated by coming into contact with 6.

[0018] On the other hand, fuel is pumped by a fuel pump (not shown) and filtered by a strainer 11. After that, it passes through the fuel passage 4a in the core 4, the pipe 13, and then into the armature 9. guided to the sky. Here, the fuel is divided into two fuel grooves 9a of the armature 9, and then , through the space between the guide hole 5b of the valve seat 5 and the valve 8, the electromagnetic attractive force When the valve body 8 is in the open state, the inclined surface of the valve body 8a and the valve seat 5 5c, and is ejected from the fuel injection hole 5a.

[0019] Next, when the drive signal from the electronic control device stops, the gap between core 4 and armature 9 is The electromagnetic attractive force disappears, and the valve 8 is pushed back by the elastic force of the compression spring 14. The valve is closed and the injection of the fuel stops. Note that the drive signal is the same as that of an internal combustion engine. The flow rate of fuel injected from the fuel injection valve is controlled by the electromagnetic coil 3 using a pulse signal synchronized with the rotation. It is determined by the application time of the signal applied to.

[0020] According to the fuel injection valve, the diameter of the base end shaft portion 8b of the valve 8 is reduced and the fuel injection valve is By increasing the depth C of the fuel groove 9a, it is possible to reduce the weight of the valve 8 while improving fuel flow. The passage area of the road can be widened. Therefore, when a large amount of fuel flows into the fuel injection valve, Also, the pressure loss due to fuel passage restriction is small, and the linearity of the flow rate characteristics is maintained over a wide range. This can be ensured. To elaborate further on this, injecting fuel The intake manifold (not shown) and the valve system of the fuel injection valve 1 in the internal combustion engine If the pressure difference in the guide hole 5b of the port 5 is constant, the injected fuel flow rate will be the same as the drive signal mark. It is proportional to the addition time. In addition, the fuel flowing into the fuel injection valve passes through a pressure regulating valve (not shown). Therefore, the pressure is regulated to a predetermined level, but if there is a restriction in the fuel passage, a large flow rate may flow. pressure loss occurs when the intake manifold and valve seat 5 are The pressure difference inside the hole 5b becomes smaller, and the proportional relationship between the injected fuel flow rate and the drive signal application time is established. can no longer be maintained. However, according to this example, the fuel communication between the armature 9 and the valve 5 is Since the passage area of the channel can be widened, the pressure loss of the fluid is small, and the flow can be maintained even at large flow rates. It is now possible to ensure linearity of quantitative characteristics, that is, a proportional relationship over a wide range. Ru.

[0021] In addition, as the diameter of the proximal shaft portion 8b of the valve 8 is reduced, the weight of the valve 8 is reduced. Since the force is reduced, the operational response of the valve 8 is improved.

[0022] Further, the groove width A of the fuel groove 9a is made smaller than the shaft diameter B of the base end shaft portion 8b. Therefore, the joint area of the armature 9 to the valve 8 can be increased. . In addition, since the mounting portion 9b of the armature 9 is made thinner by forming the concave surface 9c, In addition, laser welding or electronic beam welding is used to join the valve 8 and armature 9. Low output power is required when welding by welding means such as beam welding. Therefore, the bonding area By increasing the welding output and lowering the welding output, welding spatter can be suppressed and valve 8 and The strength of the connection with the armature 9 can be increased.

[0023] [Example 2] A second embodiment of the present invention will be described with reference to FIG. Figure 3 is a cross section similar to Figure 1. is represented. This example shows a modification of Example 1, so the same part is are given the same reference numerals. In this example, the wall thickness D of the mounting portion 9b of the armature 9 is outside the base end shaft portion 8b of the valve 8. The concave surface 9c is formed into a curved shape so that it is uniform along the circumferential surface. . According to this example, the thinner part of the mounting portion 9b of the armature 9 is smaller than that of the first embodiment. Since the welding area is also widened, the weldable range is increased and the bonding strength is further improved. It will be done.

[0024] Note that the present invention is not limited to the above-mentioned Examples 1 and 2. Changes can be made within the scope of the change. Note that two fuel grooves 9a are desired in the embodiment. However, if the required amount of joint area can be obtained for each mounting part 9b, three It may be more than that.

[0025]

[Effect of the idea]

According to the present invention, the diameter of the base end shaft of the valve is reduced and the depth of the fuel groove is increased. By making the valve lighter, it is possible to increase the passage area of the fuel passage while reducing the weight of the valve. This reduces fluid pressure loss and ensures linearity of flow characteristics over a wide range. can be done. In addition, the inertia of the valve is reduced due to the reduction in weight due to the smaller diameter of the base end shaft of the valve. As a result, the operational response of the valve is improved. In addition, by making the groove width of the fuel groove smaller than the shaft diameter of the base end shaft, the valve The joint area of the armature can be increased, and the mounting part of the armature can be The valve and armature are laser welded to reduce the wall thickness by forming a concave surface. Or is it possible to use low output power when fixing by a welding method such as electron beam welding? This also suppresses welding spatter and increases the strength of the connection between the valve and armature. I can do that. Therefore, it is necessary to ensure the strength of the connection between the valve and armature and the operational response of the valve. At the same time, the passage area of the fuel passage is widened to ensure linearity of flow characteristics over a wide range. can be maintained.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part of Example 1.

FIG. 2 is a sectional view of a fuel injection valve.

FIG. 3 is a sectional view of a main part of Example 2.

FIG. 4 is a sectional view of a main part of Conventional Example 1.

FIG. 5 is a sectional view of a main part of conventional example 2.

[Explanation of symbols]

8 valve 8b Proximal shaft part 9 Armature 9a Fuel groove 9b Mounting part 9c concave

Claims (1)

[Scope of utility model registration request] 1. A fuel injection valve having a valve having a substantially cylindrical armature fitted to a base end shaft portion, and a fuel passage provided between the base end shaft portion and the armature, wherein the inner periphery of the armature at least two fuel grooves formed in a surface, parallel to the axial direction, symmetrical about the central axis, and having a groove width smaller than the axial diameter of the proximal shaft portion of the valve;
a thin-walled mounting portion provided between the fuel grooves in the circumferential direction of the armature, fixed to the base end shaft portion of the valve by welding means such as laser welding, and having a concave surface on an outer surface thereof; Equipped with fuel injection valve.