JP2958753B2 - Electromagnetic fuel injection valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve housing having a valve seat at a front end thereof, and a valve having a valve portion at the front end which can be seated on the valve seat and formed in a rod shape and capable of moving in the axial direction. A valve body housed in the valve housing as
A movable core coupled to a rear end of the valve element, a cylindrical fixed core fixedly disposed with a front end opposed to a rear end of the movable core, and a receiver fitted and fixed to a rear portion of the fixed core A return spring provided between the member and the valve body to bias the valve body in a direction to seat the valve portion on a valve seat; and a coil assembly comprising a coil wound around a bobbin surrounding the fixed core. And a solenoid housing made of a magnetic material magnetically coupled to a rear portion of the fixed core to cover the coil assembly and to be connected to the valve housing.

[0002]

2. Description of the Related Art Conventionally, such an electromagnetic fuel injection valve is already known, for example, from Japanese Patent Application Laid-Open No. 7-259703.

[0003]

SUMMARY OF THE INVENTION In the above prior art,
A ring-shaped stopper plate that regulates a rearward moving end of the valve body is sandwiched between the valve housing and a yoke arranged on the rear side of the valve housing. By the way, the fuel injection amount is determined by the valve hole opening area of the valve housing and the operating stroke of the valve element. In the above-mentioned conventional one, the front end face of the stopper plate and the rear end face of the valve housing are ground. The operating stroke of the valve body is adjusted. For this reason, not only is a dedicated processing machine for grinding the end faces of the stopper plate and the valve housing necessary, but also the number of processing steps is increased by the amount of the grinding processing, resulting in an increase in manufacturing cost. I have.
In addition, if the chips generated by the grinding are not reliably removed, defective products may be generated, and the complicated chip removing operation will increase the number of working steps.

On the other hand, there is a type in which a movable core is brought into contact with a fixed core without using a stopper plate as described above to regulate a rearward moving end of a valve body. The surface facing the movable core and the fixed core is subjected to a surface treatment in order to prevent wear due to the surface treatment, and the number of processing steps increases by the amount of the surface treatment. In addition, the surface treatment layer provided on the opposing surfaces of the movable core and the fixed core also serves as a gap for eliminating the influence of residual magnetism caused by direct contact between the magnetic materials. It is difficult to improve the processing accuracy of the movable core and fixed core before surface treatment, the processing time and condition management to keep the surface treatment depth constant, and the accuracy of additional processing after surface treatment. Variations increase and the defect rate increases, leading to an increase in manufacturing costs.

The present invention has been made in view of such circumstances, and provides an electromagnetic fuel injection valve capable of easily adjusting the operation stroke of a valve body while reducing the number of processing steps. The purpose is to do.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a valve housing having a valve seat at a front end thereof, and a valve having a valve portion at the front end capable of seating on the valve seat. A valve body formed and accommodated in the valve housing so as to be movable in the axial direction, a movable core coupled to a rear end of the valve body, and a front end fixed to a rear end of the movable core. A cylindrical fixed core to be disposed, a receiving member fitted and fixed to a rear portion of the fixed core, and a valve provided between the valve body and biasing the valve body in a direction to seat the valve part on a valve seat. A return spring, a coil assembly in which a coil is wound around a bobbin surrounding the fixed core, and a magnetically coupled rear portion of the fixed core to cover the coil assembly and to be connected to the valve housing. Solenoid housing made of magnetic material The electromagnetic fuel injection valve comprising,
A cylindrical portion provided integrally with the front end of the solenoid housing, and a rear portion of a valve housing made of a magnetic material fitted to the cylindrical portion are welded and formed of a nonmagnetic material having a regulating surface facing forward. The guided member is fixed to both the cylindrical portion and the fixed core, and a guided member made of a non-magnetic material slidably fitted to the guide member abuts on the regulating surface and the valve body and The movable core is integrally fixed to the movable core with a regulating flange for regulating a rearward moving end of the movable core.

According to this configuration, when assembling the electromagnetic fuel injection valve, the guided member is fixed to the movable core fixed to the valve body, and from the rear end of the movable core to the rear end of the regulating flange. Is measured, and when the movable core moves at the most rearward side after assembling the electromagnetic fuel injection valve, the set distance is set to a set distance between the rear end of the movable core and the front end of the fixed core. The guide member is fixed to at least one of the cylindrical portion of the solenoid housing and the fixed core such that the regulating surface is located forward from the front end of the fixed core by a second distance obtained by adding the first distance. Next, a third distance from the regulating surface to the front end of the cylindrical portion and a fourth distance from the regulating flange to the rear end of the valve housing in a state where the valve portion of the valve body is seated on the valve seat are measured, The sum of the fifth distance and the fourth distance from the rear end of the valve housing to the front end of the cylindrical portion in a state where the rear portion of the valve housing is fitted to the cylindrical portion is equal to the third operating distance of the valve element set operation stroke. The fifth distance is determined so as to be smaller than the distance, the rear portion of the valve housing is fitted to the cylindrical portion, and the cylindrical portion and the valve housing are welded to each other in this state, so that the operating stroke of the valve body is reduced. It can be set to the set distance. Therefore,
When adjusting the operating stroke of the valve element, it is not necessary to perform machining, not only a special processing machine is unnecessary, but also the number of processing steps can be reduced. Is unnecessary, and the number of work steps can be reduced. Furthermore, it is unnecessary to perform surface treatment on the opposing surfaces of the movable core and the fixed core,
This can contribute to a reduction in manufacturing cost.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.

FIGS. 1 to 4 show an embodiment of the present invention. FIG. 1 is a vertical sectional side view showing a mounted state of an electromagnetic fuel injection valve, and FIG. 2 is an enlarged vertical sectional view of the electromagnetic fuel injection valve. Figure,
FIG. 3 is a sectional view taken along line 3-3 in FIG. 2, and FIG. 4 is an exploded longitudinal sectional view showing the state of assembling the electromagnetic fuel injection valve.

First, in FIG. 1, an intake manifold 5 connected to a cylinder head of an engine (not shown) is made of, for example, a synthetic resin, and the intake manifold 5 is integrally provided at a portion near the cylinder head. A stepped mounting hole 7 having an axis directed toward the cylinder head side is provided, and an electromagnetic fuel injection valve V corresponding to each intake port (not shown) of the cylinder head is inserted into the mounting hole 7. .

An annular chamber 8 is formed between an intermediate portion of the mounting hole 7 and the electromagnetic fuel injection valve V. The electromagnetic fuel injection valve V is formed on both sides of the annular chamber 8 along the axis of the mounting hole 7. The annular sealing members 9 and 10 mounted on the outer periphery of the
Close to the inner surface of the. The mounting portion 6 is provided with a fuel passage 11 communicating with the annular chamber 8. Fuel supplied from the fuel passage to the annular chamber 8 passes through an annular filter 12 mounted on the electromagnetic fuel injection valve V. It is introduced into the electromagnetic fuel injection valve V.

A flange 40 extending radially outward is provided at the rear (upper part in FIG. 1) of the electromagnetic fuel injection valve V. A ring-shaped elastic member attached to the outer periphery of the flange 40 is provided. 13 is sandwiched between a stepped portion 7 a provided at the rear end opening of the mounting hole 7 and a holding plate 15 fastened to the mounting portion 6 with bolts 14, thereby being inserted into the mounting hole 7. The electromagnetic fuel injection valve V is mounted on the mounting portion 6.

In FIG. 2, an electromagnetic fuel injection valve V includes a cylindrical valve housing 16 made of a magnetic material,
A valve seat member 17 fixed to the front end of the valve housing 16
And a valve portion 19 formed in a spherical crown shape so as to be seated on a hemispherical valve seat 18 provided on the inner surface side of the valve seat member 17.
Is integrally formed at the front end of the valve body 20 and is formed in a rod shape and accommodated in the valve housing 16 so as to be movable in the axial direction. A movable core 21 to be coupled, a fixed core 22 formed of a magnetic material in a cylindrical shape, and fixedly arranged with the front end facing the rear end of the movable core 21;
A rod-shaped receiving member 24 having an annular sealing member 23 that resiliently contacts the inner surface of the fixed core 22 and fitted and fixed to the rear portion of the fixed core 22 by press fitting or the like;
4 and a return spring 25 provided between the rear end of the valve body 20 and acting on the valve body 20 in a direction in which the valve portion 19 is seated on the valve seat 18, and a bobbin 26 surrounding the fixed core 22. A coil assembly 28 having a coil 27 wound thereon; and a solenoid housing 2 made of a magnetic material magnetically coupled to a rear portion of the fixed core 22 to cover the coil assembly 28 and to be connected to the valve housing 16.
9 is provided.

The valve seat member 17 is formed in a ring shape coaxially with a valve hole 30 opening at the center of the valve seat 18.
The front end of the valve housing 16 is fitted. At the front end of the valve housing 16, a cover plate 32 having an injection hole 31 coaxially connected to the valve hole 30 is fixed by beam welding or the like, and the valve seat member 17 is attached to the cover plate 32 by beam welding or the like. It is fixed. Further, a front cap 33 made of an elastic material is attached to the front end of the valve housing 16. The front cap 33 has an opening 34 having a diameter larger than that of the injection hole 31. 30 is provided coaxially.

Referring also to FIG. 3, the valve element 20 is provided with a large diameter portion 20a coaxially at a rear portion thereof. The large diameter portion 20a is fitted to a movable core 21 having a cylindrical shape. The inner periphery of the front end of the movable core 21 is fixed to the large diameter portion 20a by welding or the like.

In addition, the outer surface of the large diameter portion 20a of the valve body 20 is provided at a plurality of locations spaced apart in the circumferential direction, for example, at two locations.
Grooves 35, 35 extending in the axial direction are provided at the locations,
The flow of fuel between these grooves 35, 35 and the inner surface of the movable core 21 is allowed.

The fixed core 22 is inserted into the coil assembly 28, that is, the bobbin 26, with its front end protruding forward from the front end of the coil assembly 28. A flange portion 22a abutting on the rear end of the coil assembly 28 is integrally provided so as to protrude radially outward. On the other hand, the solenoid housing 29
Is a first cylindrical portion 29a coaxially surrounding the coil assembly 28.
And a second cylindrical portion 29c coaxially connected to the front end of the first cylindrical portion 29a via a step portion 29b and having a smaller diameter than the first cylindrical portion 29a.
The outer surface of the flange portion 22a of the fixed core 22 is fixed to the inner surface of the rear portion of the cylindrical portion 29a by beam welding or the like, so that the rear portion of the solenoid housing 29 is magnetically coupled to the rear portion of the fixed core 22. Is sandwiched between the flange portion 22a of the fixed core 22 and the step portion 29b of the solenoid housing 29.

The flange 22a of the fixed core 22 and the rear end of the first cylindrical portion 29a of the solenoid housing 29 are provided with notches 36 and 37 corresponding to each other.
A protrusion 26a projecting rearward from an opening formed by the notches 36 and 37 is provided on the bobbin 2 of the coil assembly 28.
6 are provided integrally.

The rear portion of the first cylindrical portion 29a and the rear portion of the fixed core 22 in the solenoid housing 29 are covered with a cover 38 made of synthetic resin so that the rear end of the fixed core 22 projects rearward. In addition, a synthetic resin filling portion 39 filled between the coil assembly 28 and the solenoid housing 29 is formed so as to be integrally connected to the covering portion 38 at the opening between the cutouts 36 and 37. A flange 40 for attaching the elastic member 13 shown in FIG. 1 is formed integrally with the covering portion 38, and a part of the flange 40 is embedded in the protrusion 26 a of the bobbin 26 so as to be connected to both ends of the coil 27. The coupler portion 41 that faces the members 42 is integrally formed.

A rear cap 43 is attached to the rear end of the fixed core 22 projecting rearward from the covering portion 38.

A rear portion of the valve housing 16 is fitted to a second cylindrical portion 29c provided at the front end of the solenoid housing 29, and the cylindrical portion 29c and the valve housing 16 are
They are fixed to each other over the entire circumference by beam welding or the like.
That is, the front portion of the solenoid housing 29 is magnetically coupled to the valve housing 16.

The annular seal member 9 closely contacting the inner surface of the mounting hole 7 shown in FIG. The annular seal member 10 mounted on the outer periphery of the portion 29a and in close contact with the inner surface of the mounting hole 7 is configured such that the rearward movement thereof is regulated by the front end of the second cylindrical portion 29c in the solenoid housing 29. It is mounted on the outer periphery of the housing 16. The annular filter 12
The solenoid-operated fuel injection valve V is mounted on the outer periphery of a second cylindrical portion 29c of the solenoid housing 29 so as to face the annular chamber 8 (see FIG. 1) when the solenoid-operated fuel injection valve V is inserted into the mounting hole 7. A plurality of flow holes 44 for introducing the fuel filtered by the filter 12 into the second cylindrical portion 29c and the valve housing 16 are provided in the portion 29c at intervals in the circumferential direction.

In order to guide the axial movement of the valve body 20 in the valve housing 16, a cylindrical first guide member 46 for slidably fitting the front end of the valve body 20 is provided. The first guide member 4 is fitted in the front end portion.
6 is fixed to the valve housing 16 over the entire circumference by beam welding or the like. Moreover, on the inner circumference of the first guide member 46, there are provided flow grooves 47 extending in the axial direction at a plurality of locations spaced apart in the circumferential direction.

The front of the fixed core 22 and the rear of the movable core 21 protruding from the front end of the coil assembly 28 and the second cylindrical portion 29c at the front end of the solenoid housing 29 are non-conductive. A second guide member 48 formed of a magnetic material and having a cylindrical shape is interposed. The second guide member 48 is fitted into the second cylindrical portion 29c, and is connected to the coil assembly 28 of the fixed core 22. Is fitted to the second guide member 48, and the second guide member 48 is welded to the outer periphery of the fixed core 22 over the entire periphery by beam welding or the like, and is also beam-welded to the inner periphery of the second cylindrical portion 29c. It is welded over the entire circumference.

A cylindrical guided member 50 made of a nonmagnetic material is slidably fitted to the second guide member 48. The guided member 50 is fitted to the guided member 50. It is fixed to the combined movable core 21 by beam welding or the like. Moreover, the guided member 50 is integrally provided with a regulating flange portion 51 that abuts on a regulating surface 49 formed at the front end of the second guide member 48 and regulates the movable end of the movable core 21 and the valve body 20 toward the rear side. Provided.

Next, the operation of this embodiment will be described. The front end of the valve body 20 is slidably fitted to the first guide member 46 fixed in the front end of the valve housing 16, and the first end of the solenoid blade 29. The movable core 2 is attached to the second cylindrical member 29 c and the second guide member 48 fixed to the fixed core 22.
The guided member 50 fixed to 1 is slidably fitted, so that the axial movement of the valve body 20 is guided at two places relatively spaced in the axial direction of the valve body 20. The smooth operation of the valve body 20 in the valve housing 16 is enabled.

Further, the cylindrical first guide member 46 is fitted into the front end of the cylindrical valve housing 16,
The cylindrical second guide member 48 is fitted to the second cylindrical portion 29c at the front end of the solenoid housing 29 and is fitted to the front end of the fixed core 22, and is movable by the cylindrical guided member 50. Since the cores 21 are fitted respectively, the first in the direction along the axial direction of the valve body 20
It is easy to increase the processing accuracy of the guide member 46, the second guide member 48, and the guided member 50. The regulating flange 51 is provided integrally with the guided member 50,
Since the regulating flange 51 abuts on the regulating surface 49 at the front end of the second guide member 48, the second regulating member 51 with respect to the axial direction of the
The regulating surface 49 and the regulating flange 51 at the front end of the guide member 48
It is easy to increase the accuracy of the squareness of the slab, and no special processing is required. Further, since the movable core 21 does not contact the fixed core 22, it is not necessary to perform a surface treatment on the opposing surfaces of the movable core 21 and the fixed core 22.

Further, the outer periphery of the second guide member 48 is welded to the inner periphery of the second cylindrical portion 29c of the solenoid housing 29 over the entire periphery, and projects from the front end of the coil assembly 28 to the rear end of the second guide member 48. The outer circumference of the front end portion of the fixed core 22 fitted to the second guide member 48 is welded to the entire circumference of the second guide member 48.
Sealing between the guide members 48 and between the fixed core 22 and the second guide member 48 can be achieved without the need for a sealing member, which can contribute to a reduction in the number of parts.

The assembly of such an electromagnetic fuel injection valve V will be described with reference to FIG. 4. First, a guided member 50 is fixed to a movable core 21 fixed to a valve body 20 to form the movable core 21. previously measuring a first distance L ₁ to the rear end of the restricting flange portion 51 from the rear end. In addition, when the movable core 21 moves at the most rearward position in the assembled electromagnetic fuel injection valve V, the first distance L is set to a set distance set between the rear end of the movable core 21 and the front end of the fixed core 22. as regulating surface 49 to the front side from the front end of the second distance L ₂ by a fixed core 22 which is obtained by adding ₁ to the position, the second cylindrical portion 29 of the second guide member 48 solenoid housing 29
c and fixed to the fixed core 22.

Next, the second cylindrical portion 29 is moved from the regulating surface 49 to the second cylindrical portion 29.
a third distance L ₃ to the front end of c, and a fourth distance L ₄ from the restricting flange portion 51 in a state of being seated the valve portion 19 of the valve element 20 in valve seat 18 to the rear end of the valve housing 16 Measure the second
With the rear portion of the valve housing 16 fitted in the cylindrical portion 29c of the second cylindrical portion 29c from the rear end of the valve housing 16.
a fifth distance L ₅ to the front end of the c is the sum of the fourth distance L _4,
Setting operation stroke L ₆ of the valve body 20 so as to be smaller than only (see FIG. 2) minutes the third distance L _3, i.e. _{(L 3 -L 6 = L 4} + L 5) and so as to fifth Distance L
₅ is determined, the rear portion of the valve housing 16 is fitted to the second cylindrical portion 29c, and in this state, the second cylindrical portion 29c and the valve housing 16 are welded to each other. Then, it is possible to define the operating stroke L ₆ of the valve body 20 to the set distance. Therefore, when adjusting the operation stroke of the valve body 20, it is not necessary to perform machining, so that not only a dedicated processing machine is not required, but also the number of processing steps can be reduced.
In addition, since there is no generation of chips, it is not necessary to perform a complicated operation of removing chips, and the number of working steps can be reduced.

In FIG. 4, before the solenoid housing 29 and the valve housing 16 are connected, a cover 38 made of synthetic resin, a filling portion 39, a flange 40 and a coupler 41 are formed on the solenoid housing 29 side. However, the covering portion 38, the filling portion 3
9, the flange 40 and the coupler portion 41 may be formed after the solenoid housing 29 and the valve housing 16 are combined.

Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the present invention described in the appended claims. It is possible to do.

[0033]

As described above, according to the present invention, the regulating flange provided on the guided member fixed to the movable core is brought into contact with the regulating surface formed on the fixed guide member on the solenoid housing side. By regulating the rearward moving ends of the valve body and the movable core, the fitting distance of the rear portion of the valve housing to the cylindrical portion of the solenoid housing is adjusted to weld the cylindrical portion and the valve housing to each other. By doing so, the operating stroke of the valve element can be set to the set distance, and not only a special processing machine is not required for adjusting the operating stroke, but also the number of processing steps can be reduced, and a complicated chip removing operation is performed. It is unnecessary to reduce the number of working steps, and it is not necessary to perform surface treatment, which contributes to a reduction in manufacturing cost.

[Brief description of the drawings]

FIG. 1 is a vertical side view showing a mounted state of an electromagnetic fuel injection valve.

FIG. 2 is an enlarged vertical sectional view of an electromagnetic fuel injection valve.

FIG. 3 is a sectional view taken along line 3-3 of FIG. 2;

FIG. 4 is an exploded vertical cross-sectional view showing the time of assembling the electromagnetic fuel injection valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 16 ... Valve housing 18 ... Valve seat 19 ... Valve part 20 ... Valve element 21 ... Movable core 22 ... Fixed core 24 ... Receiving member 25 ... Return spring 26. ··· Bobbin 27 ··· Coil 28 ··· Coil assembly 29 ··· Solenoid housing 29c ··· Cylindrical part 48 ··· Guide member 49 ··· Restriction surface 50 ··· Guided member 51 ··· Regulation flange V: Electromagnetic fuel injection valve

Claims (1)

(57) [Claims] A valve housing (16) provided with a valve seat (18) at a front end thereof, and a valve portion (19) at a front end capable of being seated on the valve seat (18) are formed in a rod shape. A valve element (20) accommodated in the valve housing (16) so as to be movable in the axial direction, a movable core (21) coupled to a rear end of the valve element (20), and a movable core (21); ), A cylindrical fixed core (22) fixedly arranged with the front end facing the rear end, a receiving member (24) fitted and fixed to the rear part of the fixed core (22), and the valve body (20). ), A return spring (25) for urging the valve body (20) in a direction to seat the valve portion (19) on the valve seat (18).
And a coil assembly (28) formed by winding a coil (27) around a bobbin (26) surrounding the fixed core (22).
And a solenoid housing (29) made of a magnetic material magnetically coupled to a rear portion of the fixed core (22) to cover the coil assembly (28) and to be connected to the valve housing (16). In the type fuel injection valve,
A cylindrical portion (29c) provided integrally with a front end portion of the solenoid housing (29) and a rear portion of a valve housing (16) made of a magnetic material fitted to the cylindrical portion (29c) are welded to each other and forward. A guide member (48) formed of a non-magnetic material and having a regulating surface (49) facing thereto is fixed to both the cylindrical portion (29c) and the fixed core (22),
The guided member (50) made of a non-magnetic material is slidably fitted to the guide member (48).
That the valve body (20) and the movable core (21) are integrally fixed to the movable core (21) by regulating a rearward moving end of the movable body (21). Characteristic electromagnetic fuel injection valve.