JPH05164016A - Electromagnetic type fuel injection valve - Google Patents

Abstract

PURPOSE:To easily achieve an electromagnetic type fuel injection valve making at a low cost and improve assembly property by simplifying sealing structure and reducing the number of seals for sealing fuel and forming sealing surfaces without machining. CONSTITUTION:The housing 6 of an electromagnetic fuel injection valve 1 is divided into a case 6a to hold a valve assembly 5 and a housing body 6b. The case 6a is a pipe drawing work, and the housing body 6b is a press work. A core 7 is formed by drawing a pipe, and an O-ring is secured between the sealing surface of the external periphery of the head of the core 7 and the sealing surface of the internal periphery of the base end of the case 6a. The housing body 6b is press-fitted to the external periphery of the case 6a. The seal surfaces are of non-machined ones formed by drawing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic fuel injection valve used in an electronically controlled fuel injection type internal combustion engine.

[0002]

2. Description of the Related Art As an electromagnetic fuel injection valve used in an electronically controlled fuel injection type internal combustion engine, one having a structure as shown in FIG. 3 is conventionally known. This conventional electromagnetic fuel injection valve 1 controls the injection amount of fuel by the pulse width of a drive pulse applied to an electromagnetic coil, and includes a valve body 3 having an opening 2 at the center of the tip and the opening 2. A valve assembly 5 is constituted by a needle 4 slidably mounted inside the valve body 3 so as to open and close. A housing 6 for holding the valve assembly 5 at one end is provided, and the collar portion of the core 7 arranged facing the needle 4 is fixed to the other end of the housing 6 by caulking. An annular space is formed inside the housing 6 between the core 7 and the core 7. In the annular space, a coil bobbin 8 mounted on the core 7 is provided with an electromagnetic coil 9.
A coil assembly 10 formed by winding a coil 6 is arranged, and the coil bobbin 8 has an inner diameter portion with a housing 6 and a core 7
O-rings 11 are respectively provided between and. An outer mold 12 formed by resin molding is formed so as to cover the outer periphery of the coil assembly 10, and a connector mold 14 formed by resin molding is formed so as to cover the terminal 13 connected to the electromagnetic coil 9. Also, core 7
A spring 15 for biasing the needle 4 in the closing direction is held at the tip of the. In such a configuration,
When a drive pulse is applied to the electromagnetic coil 1 via the terminal 13, an electromagnetic force is generated and the needle 4 is driven in the opening direction against the biasing force of the spring 15. Further, the fuel is supplied to the valve assembly 5 via the fuel passage formed by the inner diameter portion of the core 7.

Further, in the above structure, O is provided at two locations on the inner diameter of the coil bobbin and one location on the outer diameter of the valve assembly.
Since it is necessary to provide a ring,
In the one disclosed in Japanese Patent No. 859, the number of O-rings used is reduced by changing the configurations of the housing and the valve assembly.

[0004]

In the conventional electromagnetic fuel injection valve as shown in FIG. 3, it is necessary to provide O-rings at two locations on the inner diameter portion of the coil bobbin and one location on the outer diameter portion of the valve assembly as described above. Therefore, the number of O-rings used is large and the cost is high. Further, there is a problem that the O-ring sealing surface has to be processed with high precision, and the O-ring is easily damaged at the time of assembly. It is difficult to improve assemblability. Further, in the example disclosed in the above publication, although the number of O-rings to be used can be reduced, the structure of the valve assembly and the housing becomes complicated, and the O-ring sealing surface is located at the bottom of the housing. New problems such as chip discharge and difficult machining surface inspection will occur.

The present invention has been made in order to solve the above problems, and has a simple structure, can reduce the number of seal materials used for fuel sealing, and forms a sealing surface without post-processing such as cutting. It is an object of the present invention to obtain an electromagnetic fuel injection valve which can be manufactured at low cost and can be easily assembled.

[0006]

SUMMARY OF THE INVENTION In an electromagnetic fuel injection valve according to the present invention, a case for holding a valve assembly and a core for supporting a coil assembly are formed by pipe drawing at the tip end, and the case and the core are formed. The outer peripheral side of the coil assembly is connected to each other through the housing components made by press work, and the inner peripheral surface of the base end of the case and the outer peripheral surface of the tip end of the core are made into a non-cutting seal surface by drawing, and the fuel between these seal surfaces The configuration is such that a sealing material for sealing is arranged.

[0007]

According to the present invention, the case forming the valve holding portion is a pipe drawn product which is separate from the housing, and the core is also a drawn product, and the housing component formed by press working is used. By positioning the case and the core with respect to each other, the shape of each member constituting the electromagnetic fuel injection valve and the structure as a whole are simplified, and the assembly is facilitated. The inner peripheral surface or the outer peripheral surface of the case and the core, both of which are pipe drawn products, is a sealing surface without post-processing such as cutting only by drawing, and an O-ring or the like is provided between the sealing surfaces. Fuel is reliably sealed by inserting the sealing material. Further, since the case, core, and housing constituent members are pipe drawn products or pressed products as described above, secondary processing is not required and cost can be reduced.

[0008]

FIG. 1 is a sectional view showing a first embodiment of an electromagnetic fuel injection valve according to the present invention, and FIG. 2 is a structural view of parts of this electromagnetic fuel injection valve.

In this embodiment, the electromagnetic fuel injection valve 1
A valve assembly 5 is composed of a valve body 3 having an opening 2 at the center of the tip and a needle 4 slidably mounted inside the valve body 3 to open and close the opening 2. Further, the housing 6 is divided into a case 6a for holding the valve assembly 5 and a housing body 6b. The case 6a is a pipe drawing product, and the housing body 6b is a pressed product, and the flat plate material is formed into a tubular shape after pressing. It is said to have been molded. Also, the housing body 6b
A core 7 is arranged inside of the so as to face the needle 4 and to be inserted into the base end portion of the case 6a by a predetermined size.

The valve assembly 5 is inserted into the case 6a, positioned on a step portion of the case 6a via a stopper 16, and fixed by welding. Further, a spring 15 for urging the needle 4 in the closing direction is attached to the tip of the core 7.

The core 7 is formed in a stepped shape with a small diameter on the tip side by pipe drawing, the inner diameter portion constitutes a fuel passage, and the large diameter side of the stepped portion is formed by pressing top. The plate 17 is press-fitted. Further, the outer peripheral surface of the distal end of the core 7 and the inner peripheral surface of the base end portion of the case 6a facing each other are both O-ring sealing surfaces as drawn. A coil assembly 10 formed by winding an electromagnetic coil 9 around a coil bobbin 8 is mounted on the small diameter side of the core 7, and an O-ring 11 is mounted on the tip. And in this state, core 7
Is assembled to the case 6a, and then the housing body 6a is press-fitted and fixed to the outer periphery of the case 6a from the tip (lower side in FIG. 1) side. Further, the connector mold 14 that holds the terminal 13 is extended and is an integral resin mold that covers the entire outer circumference of the coil assembly 10 and the housing body 6b.

In the electromagnetic fuel injection valve 1 of this embodiment, as described above, the case 6a and the core 7 are formed by pipe drawing, and the housing body 6b and the top plate 17 are formed by press working. Since the assembly 5 and the coil assembly 10 are positioned, the structure is simple and the assembly is easy. In addition, it is easy to secure the sealing property of each joint, only one O-ring 11 is required, and the O-ring sealing surface is drawn and does not require post-processing such as cutting.

[0013]

As described above, according to the present invention, the housing is divided into the case constituting the valve holding portion and the housing body side, the case and the core are formed by pipe drawing, respectively, and the housing constituent member is formed. Since it is formed by press working, the inner peripheral surface of the base end portion of the case and the outer peripheral surface of the tip end portion of the core are formed as non-cutting seal surfaces by drawing, and a seal material for fuel sealing is arranged between these seal surfaces. The structure is simple, the processing is easy, the number of sealing materials used can be reduced, and the sealing surface can be formed without post-processing such as cutting.
Low cost and easy assembly can be easily achieved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an electromagnetic fuel injection valve according to the present invention.

FIG. 2 is a structural diagram of parts in an embodiment of an electromagnetic fuel injection valve according to the present invention.

FIG. 3 is a sectional view showing a conventional electromagnetic fuel injection valve.

[Explanation of symbols]

 1 Electromagnetic Fuel Injection Valve 5 Valve Assembly 6a Case 6b Housing Body 7 Core 10 Coil Assembly 11 O-ring

Claims (1)

[Claims] 1. A case for holding a valve assembly and a core for supporting a coil assembly at a tip end are formed by pipe drawing, respectively, and the case and the core are mutually connected on the outer peripheral side of the coil assembly via a housing constituent member formed by press working. In addition, the inner peripheral surface of the base end portion of the case and the outer peripheral surface of the tip end portion of the core are formed as uncut sealing surfaces by drawing, and a sealing material for fuel sealing is arranged between these sealing surfaces. Electromagnetic fuel injection valve.