JP2001280213A - Miniaturized injector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize an injector to a great extent. SOLUTION: The injector is composed of a cylinder 32 to form a fuel passage having a fuel jet 4B at the tip, a valve 9 to open and close the jet 4B, a solenoid coil 18 to open the valve 9, an energizing means 34 to energize the valve 9 in the direction of valve closing, and a terminal 28 whereto a power cable for feeding current to the solenoid coil is connected. The solenoid coil 18 has in itself an ability to maintain a cylindrical shape and has no bobbin, and accordingly the injector can be miniaturized directly. The non-bobbin construction allows shortening of the magnetic path to lead to suppression of the magnetic resistance, to allow lessening of the number of coil turns, which also contributes to miniaturization of the injector.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a miniaturized injector.

[0002]

2. Description of the Related Art A conventional injector energizes a solenoid coil to attract a valve by electromagnetic force, and moves a valve urged to a closed position to an open position. Since this solenoid coil is formed by winding a thin conductive wire many times, conventionally, a pin winding (also called a bobbin) is used, and a thin conductive wire is wound around the winding many times to form a solenoid coil. I was

[0003]

According to this solenoid coil, a space for accommodating the volume of the bobbin is required in the injector, which hinders downsizing of the injector. The present invention further reduces the size of the injector.

[0004]

SUMMARY OF THE INVENTION An injector according to the present invention comprises a tubular portion forming a fuel passage having a fuel injection hole at a tip, a valve for opening and closing the fuel injection hole, and a solenoid for opening the valve. A coil, an urging means for urging the valve to the valve closing side, and a terminal for connecting to a power line for energizing the solenoid coil are provided. The injector according to the invention is particularly characterized in that its solenoid coil has the ability to maintain its own coil shape and has no thread winding. According to this injector, it is possible to directly reduce the size of the injector by an amount that does not require thread winding. Furthermore, if there is no thread winding, the magnetic path can be shortened accordingly,
Since the magnetic resistance can be suppressed, the number of coil turns can be reduced, which also enables the injector to be downsized.

In the case of the above injector, the solenoid coil is formed of a conductive wire having a square (rectangular or square) cross section, and a fusion layer covering the surface of the wire is fused to maintain a cylindrical shape by itself. Preferably have the ability to do so. According to this solenoid coil, the coil can be formed without leaving a gap between the wires,
The outer dimensions of the coil can be reduced while securing the necessary wire cross-sectional area. Furthermore, if the fusion layer covering the surface of the wire is fused to obtain the ability to maintain the cylindrical shape by itself, the ability to maintain the shape is high, and the assembling work is simplified.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, features of the present embodiment will be listed. (1) The injector according to claim 1, wherein the solenoid coil has an ability to maintain a cylindrical shape by itself. According to this injector, the solenoid coil can be mounted directly around the cylinder forming the fuel passage without any gap, and the injector is effectively reduced in size.

(Embodiment 2) The injector according to Embodiment 1 or Embodiment 1, wherein the solenoid coil is formed of a conductive wire having a rectangular or square cross section. In this solenoid coil, when the solenoid coil is viewed in a cross section along the axis, there is no gap between the wires, and it is possible to secure the total value of the necessary wire cross section in a small coil cross section.

[0008] (Embodiment 3) In the solenoid coil, the fusion layer covering the surface of the conductive wire has the ability to fuse and maintain its own shape, characterized in that the solenoid coil The injector according to 1. (Embodiment 4) The solenoid coil is mounted directly on the outer periphery of the cylinder.
The injector according to any one of the above. (Mode 5) The solenoid coil of the injector body is
The injector according to the fourth aspect, wherein the injector is assembled so as to be able to adjust an axial position around an outer periphery of the first cylindrical portion. According to this embodiment, the responsiveness of the injector can be adjusted by adjusting the axial position. (Embodiment 6) The injector according to any one of Embodiments 1 to 5, wherein the terminal extends in parallel with the rear end of the cylindrical portion.

[0009]

FIG. 1 shows a group of parts of a unitized injector assembly. (A) and (C) show injector A, which is commonly used regardless of the type of injector assembly. (E) to (J) show a group of extension adapters C, one of which is selected and used. (B) and (D) show a state in which one type of extension adapter (in this case, long type CL) is connected to the injector A to form the injector assembly B.

[0010] The extension adapter group C includes a short type CS shown in (E), a medium type CM shown in (F), and (G).
The long type CL shown in FIG. The short type CS is selected when the distance between the injector mounting position on the engine side and the fuel pipe is short, and the medium type CM
Is selected when the distance is intermediate, the long type CL
Is selected if the distance is long.

[0011] There are also finer types of types having the same distance. For example, with respect to the standard long type CL shown in (G), (H) has a position where the power line terminal is connected at the tip end side. CL1 and (I) are used when the terminal shape of the power line is different. CL2 and (J) are those where the shape of the connection portion C4 to the fuel pipe is different.
L3 is shown. The variations shown in (H) to (J) exist in both the short type CS and the medium type CM.

[0012] The extension adapter C group shown in (E) to (J) is
In any case, the shape of the connecting portion C2 with respect to the rear end portion 32A of the cylindrical portion forming the fuel passage of the injector A is the same,
Any extension adapter C can be connected to injector A.

The extension adapter C shown in FIGS.
Each of the groups includes the terminals 28A and 28B of the injector A.
(Hereinafter collectively referred to as 28) and the shape and position of the second terminals C1 (to be precise, there is a pair, but collectively referred to as the second terminals C1 here) are the same. The extension adapter C can be connected to the injector A. That is, when the connection portion C2 of an arbitrary extension adapter C is connected to the rear end portion 32A of the injector A, the first terminal 2
8 is connected to the second terminal C1. Since the first terminal 28 extends in parallel with the rear end 32A of the cylindrical portion, the connection of the fuel passage and the connection of the terminals are completed simultaneously in a single operation.

[0014] In the short type CS, the distance between the connecting portion C2 to the injector A and the connecting portion C4 to the fuel pipe is short, and in the medium type CM, the distance is intermediate.
In the long type CL, the distance is long. In the case of (H),
In the case of (I), the position of the third terminal C3 to be connected to the terminal of the power line is in the front, and the shape of the third terminal C3 is different. In the case of (J), it is possible to cope with a case where the shape of the connecting portion C4 for the fuel pipe is different and the shape of the injector mounting portion on the fuel pipe side is not a standard type.

[0015] The injector A is smaller than the conventional mass-produced product, and has the same size as the conventional injector when the extension adapter C is connected to the injector assembly B shown in FIG. Become.

FIG. 2 is a sectional view of the injector A. In the figure, reference numeral 32 denotes a cylinder formed of a magnetic material, inside which a fuel passage is formed. The valve seat body 4 is fixed to the tip of the cylinder 32. The valve seat 4 has a cylindrical outer shape,
Is pressed into the inner circumference of A cylindrical hole 4D is opened from the rear inside the valve seat body 4 and a conical surface 4A is formed on the tip side.
Is formed, and the front end of the conical surface 4A opens to the front end surface of the valve seat body 4 to form a fuel injection hole 4B. 4D cylindrical hole
Functions as a guide surface for guiding the spherical valve tip 10 in the axial direction, and the conical surface 4A functions as a seal surface that abuts the spherical valve tip 10 and closes the fuel injection hole 4B. Around the cylindrical hole 4D, fuel passages 4C extending in the axial direction are formed at three positions equidistant in the circumferential direction.

A plate 6 is fixed to the tip of the valve seat 4. The plate 6 is fixed to the valve seat body 4 at a ring-shaped welding portion 8. A plurality of small holes 6A are formed in the plate 6, and the fuel injected by the small holes 6A is atomized and the injection direction is determined. After the valve seat 4 and the plate 6 are press-fitted into the cylinder 32, the tip of the cylinder 32 is caulked and positioned in the cylinder 32.

[0018] Behind the valve seat 4, a valve 9 is accommodated in the cylinder 32 so as to be movable in the axial direction. The valve 9 is a spherical valve tip 1
0 and the shaft portion 12 are formed by laser welding at the connection portion 11. As described above, the tip of the valve 9 is guided so that the spherical valve tip 10 cannot move in the radial direction but can move in the axial direction by the cylindrical hole 4D. The rear end of the valve 9 is guided by the cylinder 32 so that the enlarged diameter portion 12D cannot move in the radial direction but can move in the axial direction. Small diameter portion 1 of shaft portion 12
2B is provided with holes 12A at two locations on the diameter,
Fuel can pass from the inside of the shaft portion 12 to the outside. Shaft 12
, Or at least the enlarged diameter portion 12D is magnetized.

Inside the cylinder 32, behind the valve 9, a pipe 36 made of a magnetic material is press-fitted and fixed. A ring-shaped portion 36 </ b> A constricted inward is formed substantially at an intermediate portion of the pipe 36 in the axial direction distance, and the ring-shaped constricted portion 36 is formed.
A compression spring 34 is accommodated between A and the valve 9 in a compressed state. The distal end side of the compression spring 34 has a ring-shaped flange portion 12 between the enlarged diameter portion 12D and the small diameter portion 12B of the shaft portion 12 of the valve 9.
C received.

Since the pipe 36 is fixed to the cylinder 32,
The compression spring 34 urges the valve 9 toward the distal end, and the spherical valve distal end 1
0 abuts on the seat surface 4A of the valve seat 4 and the fuel injection holes 4B
Is closed. The valve 9 is closed by the force of the spring 34.

On the outer periphery of the cylinder 32, there is provided a solenoid coil 18 for attracting the valve 9 to the pipe 36 side by magnetic force and separating the valve 9 from the seat surface 4A (ie, opening the valve) to inject fuel from the injection hole 4B. It is assembled. Solenoid coil 1
8 is positioned on the outer periphery of the cylinder 32 by the cylindrical outer core 16 and the disk-shaped yoke 20. As shown in FIG. 1A, a wiring connecting the solenoid coil 18 and the first terminal 28 and a resin molded body 22A formed around the wiring pass through the rear end of the cylindrical outer core 16 as well shown in FIG. The opening is notched.

FIG. 3 shows a solenoid coil 18, which is formed by winding a conductive wire having a rectangular or square cross section in a cylindrical shape. This wire is covered with an insulating layer around a conductive core, and the surface of the insulating layer is coated with a fusion layer.The fusion layers are fused together in a state wound in a cylindrical shape. The solenoid coil 18 itself maintains a cylindrical shape. Polyvinyl butyral for the fusion layer,
Nylon and epoxy are preferably used. In the fusion treatment, a solvent is used or fusion is performed by applying heat. The solenoid coil 18 is miniaturized because it does not have a conventionally used bobbin. Also, since a wire with a rectangular or square cross section is used, there is no gap in the contact portion between the wires when wound in a cylindrical shape, and a solenoid coil made by winding a wire with a circular cross section to obtain the same magnetic flux The volume can be reduced in comparison. That is, when viewed in a cross section along the axis of the solenoid coil, a gap is created between coils in a solenoid coil made by winding a wire having a circular cross section, whereas a gap is created between coils in a solenoid coil made by winding a wire having a square cross section. In the case where the total cross-sectional area of the conductor is the same, using a wire having a rectangular cross section can reduce the size of the solenoid coil.

Since the solenoid coil 18 having no thread winding and having no gap between the wires is used, and this solenoid coil is directly mounted on the outer periphery of the cylinder 32 without any gap, the injector A can be extremely miniaturized. 1B can be suppressed to about half of the conventional size shown in FIG. Injector assembly B succeeded in this miniaturization
Can be separated into an injector A and an extension adapter C to form a unit.

As shown in FIG. 3, a resin plate 30 is disposed behind the solenoid coil 18. Resin board 3
At 0, a metal plate serving as a pair of terminals 28A and 28B is insert-molded to position the pair of terminals 28A and 28B. The resin plate 30 connects a pair of terminals of the solenoid coil 18 to the terminals 28A and 28B, respectively.
Keep connected to.

As shown in FIG. 2, the solenoid coil 18 and the resin plate 30 are positioned by the outer core 16 and the yoke 20. At this time, the washer 15 is used so that the solenoid coil 18 does not move inside the outer core 16. The outer core 16 and the yoke 20 are pressed into the outer periphery of the cylinder 32, and their axial positions are determined.

The outer core 16, the cylinder 32, at least the enlarged diameter portion 12D of the valve 9, the pipe 36, and the yoke 20 are made of a ferromagnetic material. However, in the vicinity of the pipe 32 where the enlarged diameter portion 12D of the valve 9 and the pipe 36 are in contact with each other, the cylinder 32 is made non-magnetic over the entire circumference. For this purpose, the solenoid coil 1
When electricity is supplied to the outer core 8, the outer core 16 returns to the outer core 16 through the cylinder 32, the enlarged diameter portion 12D of the valve 9, the minute space between the enlarged diameter portion 12D of the valve 9 and the pipe 36, the pipe 36, and the yoke 20. A magnetic path is formed. As a result, the valve 9 is sucked toward the pipe 36 against the force of the spring 34 and the fuel injection hole 4B
Can be opened.

The magnetic resistance of the magnetic path varies depending on the axial position of the solenoid coil 18 with respect to the cylinder 32. Therefore, the force for attracting the valve 9 toward the pipe 36 by the solenoid coil 18 and, consequently, the time from the start of energization to the solenoid coil 18 to the opening of the valve 9 also vary depending on the axial position of the solenoid coil 18 with respect to the cylinder 32. In this injector A, after the injector A is assembled, the axial position of the outer core 16 and the yoke 20 is adjusted, and the responsiveness of the injector, that is, the solenoid coil 1 is adjusted.
The time from the start of energization to 8 until the valve 9 opens is adjusted to a fixed time. According to this adjustment method, a device for adjustment can be easily manufactured. Further, the adjustment time can be shortened. Furthermore, conventionally, the pipe 36
In this embodiment, the solenoid coil 18 can be adjusted to both the front end side and the rear end side. Does not have the above disadvantages. If a spool is used for the solenoid coil, the magnetic path will surround the spool and become longer. In the present embodiment, since the solenoid coil 18 having no pin winding is directly mounted on the outer periphery of the cylinder 32, the magnetic path is short and the magnetic resistance is small.
To obtain the required magnetic attraction force.

In FIG. 2, reference numeral 14 denotes an O-ring for keeping the connection between the injector A and the engine side airtight.
Is an O-ring for keeping the connection between the injector A and the extension adapter C airtight, and 26 is a filter for removing foreign matter from the fuel. Reference numeral 2 denotes an adapter that covers the tip of the injector A, and reference numeral 22 denotes a resin disk 30 and the yoke 2.
2 and a cover that covers the outer periphery of the rear end of the outer core 16;
In both cases, the resin is formed by injection molding. The resin cover 22 has a substantially cylindrical shape. However, as shown in FIG. 1A, the resin terminal 22 protrudes laterally at a portion where the first terminal 28 exists, and serves as a base of the first terminal 28.

FIGS. 4 and 5 show an extension adapter C
Is shown in FIG. As shown in FIG. 4, the extension adapter C has a pair of metal pieces 40 inside.
E and 40F are integrally formed by a resin molded product 42 which is insert-molded. The pair of metal pieces 40E and 40F
Each has at one end a second terminal 40 for receiving the first terminal.
A and 40B, and the other end has third terminals 40C and 40D for connecting terminals of the power line. In FIG. 4, a pair of metal pieces 40E and 40F are displayed in an overlapping manner, and only the symbols are doubled. Each second terminal 40A, 40B
Receives the first terminals 28A and 28B between two metal plates. Each of the third terminals 40C and 40D projects obliquely upward with respect to the axial direction. A fourth terminal is attached to each end of the pair of power lines, and each of the fourth terminals is a third terminal 40C between two metal plates.
Accept 40D. The second terminals 40A, 40B are collectively indicated by C1 in FIG. Third terminals 40C, 40
D are collectively designated C3 in FIG.

[0030] The resin molded article 42 is integrally formed of resin and has the following shape. Reference numeral 42A denotes a cylindrical portion that receives a terminal-equipped plug at the end of the power line. Reference numeral 42B is a wall that forms a cylinder, and forms a fuel passage 42F inside. Reference numeral 42C denotes a connection to the fuel pipe (indicated by C4 in FIG. 1), and the O-ring 44 keeps the connection between the fuel pipe and the extension adapter C airtight. 42D and 42E are injector A
The O-ring 24 receives the injector A and the extension adapter C.
Connection is kept airtight. Tube part 32 of injector A
The connecting portions 42D and 42E to the rear end portion 32A are collectively indicated by C1 in FIG. Reference numeral 42G denotes a tubular portion which receives the rear end of the resin cover 22 of the injector A and covers the same from outside. However, the cylindrical portion 42G is cut out at a part in the circumferential direction to receive the base 22A of the first terminal 28 of the injector A. As shown in FIG. 5, the cylindrical portion 42G has through holes 42H at two locations on the diameter.

The resin cover 22 is formed with springs 22B projecting outward at two locations on the diameter corresponding to the through holes 42H. When the extension adapter C is connected to the injector A, the spring 22B protrudes into the through hole 42H to prevent the injector A and the extension adapter C from coming off. The stopper of the injector A and the extension adapter C may be snap-fitted by the spring 22B and the through-hole 42H, or may be welded, press-fitted or bonded to prevent the removal. Alternatively, both may be stopped by using a connection clip.

An injector assembly B formed by connecting the extension adapter C to the injector A is used between the engine side and the fuel pipe, similarly to the conventional injector, and is used between the third terminals 40C and 40D. Are connected and used.

Obviously from the above, the function of controlling the fuel injection is achieved by the injector A. The extension adapter C extends the fuel passage of the injector A in accordance with the distance between the fuel pipe and the mounting portion of the injector on the engine side, and is integrally formed of resin. Even if various types of extension adapters C are prepared, they can be originally manufactured at low cost, and do not pose a major problem. On the other hand, the injector A has a sophisticated mechanism incorporated therein, and the manufacturing cost is high. According to this unitized injector, since the same injector A can be used against the variation in the distance between the fuel pipe and the mounting portion of the injector on the engine side, a sufficient mass production effect can be obtained for the injector A whose manufacturing cost is high. As a result, the manufacturing cost per injector or injector assembly can be significantly reduced.

The above-described injector A can be used by being connected to the extension adapter C, but can also be directly connected to the fuel pipe 60 as shown in FIG. Where 12
Reference numeral 2 denotes a resin cover of the injector A, from which a pair of spring pieces 122A protrude. This injector A can be manufactured only by changing the mold for forming the resin cover 22 shown in FIG. 1, and the other parts are the same as those in FIG. The fuel pipe 60 has an opening 60C (which communicates with the fuel passage) for receiving the rear end 32A of the injector A, a recess 60B for receiving the resin cover 122, and a second terminal for receiving the first terminals 28A, 28B. (This is shaded and not shown. The second terminal is connected to a power line embedded in the wall of the fuel pipe 60.) A pair of through holes 60A for receiving a pair of spring pieces 122A are formed. ing.

Also in this case, the pair of first terminals 28A, 28B
Extends parallel to the rear end portion 32A of the tubular portion, so that the connection between fuel and electricity is completed only by inserting the injector A into the fuel pipe 60. In the component assembly obtained in this way, since the size of the injector is reduced, the distance between the fuel pipe and the engine can be reduced, and the size of the engine room can be easily reduced.

According to the present invention, the injector can be significantly reduced in size.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of a unitized injector assembly.

FIG. 2 is a diagram showing a cross section of an injector.

FIG. 3 is a perspective view showing a solenoid coil part.

FIG. 4 is a sectional view showing a state where an extension adapter is connected to the injector.

FIG. 5 is an external view of the state shown in FIG. 4;

FIG. 6 is a diagram illustrating an assembly in which an injector is directly connected to a fuel pipe.

[Explanation of symbols]

 A: Injector B: Injector assembly C: Extension adapter 28: Terminal 32: Tubular portion 18; Solenoid coil

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kazuaki Koyanagi 1-1 1-1 Kyowa-cho, Obu City, Aichi Prefecture Ai San Industry Co., Ltd. F-term (reference) 3G066 AB02 BA61 CB05 CC06U CC15 CC24 CD04 CD10 CD21 CE25 CE30 CE31

Claims (2)

[Claims] 1. A cylinder forming a fuel passage having a fuel injection hole at a tip thereof, a valve for opening and closing the fuel injection hole, a solenoid coil for opening the valve, and biasing the valve toward a valve closing side. And a terminal for connecting to a power line that energizes the solenoid coil, and the solenoid coil itself has the ability to maintain the coil shape and does not have a pincushion. Injector. 2. The method according to claim 1, wherein the solenoid coil is formed of a conductive wire having a square cross section, and a fusion layer covering a surface of the wire has a capability of being fused and maintaining a cylindrical shape by itself. The injector according to claim 1.