JPS63186960A - Fuel injection valve - Google Patents

Abstract

PURPOSE:To eliminate a core to reduce a cost and improve the responsiveness, by forming a valve member into a cylindrical shape and sliding an outer peripheral portion of the valve member in a guide hole, and also to easily adjust a fuel flow by pressfitting a seat member. CONSTITUTION:A connector pipe 23 is fixed to a rear end of a housing 21, and a solenoid coil 29 is provided around the connector pipe 23. A valve member 22 is axially slidably inserted in a guide hole 21a formed in the housing 21, and when the solenoid coil 29 is supplied with current, the valve member 22 is lifted. The valve member 22 is formed of a magnetic material and has a cylindrical shape such that it is formed at its front end with a seat surface 26a and has a fuel passage 22a therein. A seat member 27 is press-fitted into a front end portion of the guide hole 21a. The seat member 27 has a seat portion 27a on which the seat surface 26a of the valve member 22 is seated, and also has a nozzle hole 27b. A nozzle spring 32 is provided under compression between the valve member 2 and an adjust pipe 31 inserted in the connector pipe 23.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a fuel injection valve used in an electronic fuel injection device (EFI), etc., which injects fuel by lifting the valve body by energizing an electromagnetic coil. Regarding.

(Prior Art) As a conventional fuel injection valve, the one shown in FIG. 5, for example, is generally known. This fuel injection valve 1 has a needle valve 6 slidably inserted in a nozzle body 5 that has a nozzle 2 and an oil reservoir 3 at its tip and a guide hole 4 inside. The needle valve 6 is formed solid, has a seat surface 6a at its tip portion to be seated on the seat portion 5a of the nozzle body 5, and has a front guide 6b and a rear guide guided to the guide hole 4 in its body. 6c, and a core 7 is fixed to the rear end by caulking or the like. The core 7 is inserted into the housing 8, and a gap is formed between the core 7 and the housing 8 so that the core 7 does not come into contact with the housing 8. A housing 8 is integrally fixed to the rear end of the nozzle body 5, and a spacer 9 is interposed between them to restrict the lift operation of the needle valve 6. The housing 8 has a connector pipe lO
is fixed, and an electromagnetic coil 11 is provided around the connector pipe IO. Further, an adjustment pipe 12 is inserted through the connector pipe 12 side, and a nozzle spring 13 is compressed between the adjustment pipe 12 and the core 7. Adjustments are made. The housing 8, the connector pipe 12, and the core 7 are made of a magnetic material, and the electromagnetic coil 1 is made of a magnetic material.
1 magnetic circuit is formed as shown by the two-dot chain line in the figure. Then, the core 7 is attracted to the connector pipe 12 side by the electromagnetic force generated by energizing the electromagnetic coil 11 and the needle valve 6 is lifted.
is sprayed from.

(Problems to be Solved by the Invention) However, in the above-mentioned conventional fuel injection valve, the seat surface, the seat portion, the guide hole, the guide portion, etc. are precisely processed in order to maintain the oil-tightness of the seat portion. However, since the core is fixed to the rear end of the solid needle valve,
As the machining errors of the above parts accumulate and affect the gap, the dimensions of the gap must be increased to absorb these errors, and this increases the magnetic resistance of the magnetic circuit, causing the needle valve to There are problems in that it is difficult to improve the responsiveness of the process, and the processing cost increases as processing precision improves.

In addition, the tolerance of the static flow rate defined by the nozzle area is very small (about 3%), and when adjusting the static flow rate in the past, in order to adjust the static flow rate, it is necessary to first measure the flow rate and then adjust the static flow rate. However, this has to be done by removing the nozzle body and lapping or polishing the nozzle little by little.There is a problem that the flow rate can only be adjusted while measuring the flow rate, and the adjustment work is troublesome and takes a long time. Furthermore, if the nozzle is machined too large, it may result in a defective product, which may lead to an increase in cost.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a fuel injection valve in which the response performance of the valve body is improved, flow rate adjustment is simplified, and processing costs can be reduced.

(Means for Solving Problems and Effects thereof) The fuel injection valve according to the first invention includes an electromagnetic coil disposed around a connector pipe fixed to the rear end side of the housing, and a shaft mounted in a guide hole in the housing. It has a valve body that is inserted so as to be slidable in a direction and lifts when the electromagnetic coil is energized, and the valve body is formed of a cylindrical magnetic material having a seat surface at the tip and a fuel passage inside, A seat portion and an injection r+1 position where the seat surface of the valve body is seated at the tip of the guide hole. ↓Numbers〉Port = 116 Blue Cord - Leh Nozzle It is constructed by compressing a nozzle spring between the adjustment pipe inserted into the valve and the valve body, so that the valve body has a cylindrical shape. The entire outer periphery slides inside the guide hole, eliminating the need for a conventional core, making the gap in the magnetic circuit extremely small, and improving the responsiveness of the valve body as magnetic resistance is reduced. It is possible to improve the performance and reduce the number of parts. Furthermore, since the static flow rate can be adjusted by gradually press-fitting the sheet member into the tip of the guide hole while measuring the flow rate, the flow rate adjustment becomes easy.

Next, in the fuel injection valve according to a second aspect of the invention, an electromagnetic coil is arranged around a connector pipe fixed to the rear end side of the housing, and the electromagnetic coil is inserted into the guide hole in the housing so as to be slidable in the axial direction. It has a valve body that lifts when the electromagnetic coil is energized, and the valve body is made of a cylindrical magnetic material having a seat surface at its tip and a fuel passage inside, and the valve body is made of a cylindrical magnetic material having a seat surface at its tip and a fuel passage inside. A seat member having a seat portion and a nozzle on which the seat surface of the valve body is seated is press-fitted, and a nozzle spring is compressed between the connector vibe and the valve body. can be made very small, and while measuring the static flow rate and the dynamic flow rate, which is the flow rate per constant pulse width applied to the electromagnetic coil, the tip part in the guide hole of the sheet member By gradually press-fitting the fluid, the static flow rate and the dynamic flow rate can be adjusted, making it easy to adjust both flow rates and reducing costs.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a longitudinal cross-sectional view showing a fuel injection valve 20 according to the first invention, in which 21 is a housing, 21a and 21b are guide holes formed in the housing 21, and storage chambers for an electromagnetic coil 29; 22 is a valve body inserted into the guide hole 1a, 23 is a connector pipe fixed to the rear end of the housing 21, 24 is a filter, and 25 is a connector pipe 2
This is a power connector part fixed around 3.

The valve body 22 is formed into a cylindrical shape with a fuel passage 22a inside, and is made highly hard by heat treatment. Also,
The valve body 22 has a small diameter at its tip side, and a steel ball 2 whose circumferential surface is a seat surface 26a is attached to the tip of the small diameter portion.
6 are joined. Further, a seat member 27 having a seat portion 27a on which the seat surface 26a of the valve body 22 is seated and M number of nozzles 27b is press-fitted into the tip of the guide hole 1a, and is fixed at a predetermined position by caulking. Ru. An oil reservoir 28 is formed in the guide hole 1a by the housing 21, the valve body 22, and the seat member 27, and a plurality of communication holes 22b that communicate the oil reservoir 28 with the fuel passage 22a in the valve body 22 are connected to the valve body 22. It is installed in the small diameter part of the body.

Further, an electromagnetic coil 29 disposed around the extending portion 23a of the connector pipe 23 is stored in the storage chamber 21b in the housing 21, and this electromagnetic coil 29 is attached to a resin connector portion fixed to the connector pipe 23. 25 connection terminal 2
5a. The housing 21. Valve body 22
The connector pipe 23 is made of a magnetic material and forms a magnetic circuit of the electromagnetic coil 29. Inside the extending portion 23a of the connector pipe 23, a stop ring 30 for regulating the maximum lift amount of the valve body 22 has its tip protruding slightly from the tip of the extending portion 23a by a distance of □. They are fixed by press fitting while maintaining the gap 1z. An adjustment pipe 31 is inserted into this stop ring 30 and connector pipe 23.
A nozzle>0 spring 32 is compressed between the valve body 22 and the nozzle spring 32 by an adjustment pipe 31.
Dynamic flow rate adjustment is performed by finely adjusting the spring set load, and after adjustment, the adjustment pipe 31 is fixed to the connector pipe 23 by caulking or the like.

Note that the dynamic flow rate refers to the flow rate per 1 pulse applied to the electromagnetic coil 29, and the fuel flows into the oil reservoir 28 through the connector pipe 23, the adjustment pipe 31, the fuel passage in the valve body 22, and the communication hole 22b. As supplied,
When the electromagnetic coil 29 is energized, the valve body 22 is attracted toward the connector pipe 23 and lifted, the nozzle 27b of the seat member 27 is opened, and fuel is injected from the nozzle 27b.

In such a fuel injection valve 20, the static flow rate can be adjusted by gradually press-fitting the seat member 27 while measuring the flow rate. That is, as shown in FIG. 2, when the gap area between the valve body seat surface 26a and the seat portion 27a is smaller than the nozzle area (that is, when the lift of the valve body 22 is small), the static flow rate is calculated as follows. In the opposite case, it is determined by the area of the nozzle, and in the intermediate fo, it changes gently due to the influence of both. Therefore, as the lift amount of the valve body 22 changes by gradually press-fitting the seat member 27, the seat member 27 is adjusted so that the static flow rate is within the tolerance while measuring the static flow rate.
The static flow rate can be adjusted by press-fitting it to an appropriate position and fixing it by caulking when the specified flow rate is reached.

Therefore, the static flow rate can be easily adjusted in a short time without removing the nozzle body and lapping the nozzle port as in the conventional method, and it is possible to reduce costs. In addition, in the fuel injection valve of this embodiment, the core is not fixed as in the conventional case, but slides in the guide hole on the circumferential surface of the cylindrical valve body, so the number of parts can be reduced and manufacturing can be done at low cost. At the same time, the gap in the magnetic circuit between the valve body and the housing can be reduced to 1/10 or less of the conventional size, magnetic resistance is significantly reduced, and responsiveness of the valve body can be improved.

Next, an embodiment according to the second invention will be described based on FIG. 3.

The fuel injection valve 40 of this embodiment has a nozzle spring 32 interposed between the valve body 22 and the stopper ring 30, as shown in FIG. 3, and eliminates the need for the adjust pipe 31 shown in FIG. It is. This eliminates the need for fine adjustment of the spring set load using an adjustment pipe by improving the accuracy of the hole drilling in the seat part so that the static flow rate can be kept within tolerance. Namely.

As shown in FIG. 4, even if a constant pulse is applied to the electromagnetic coil 29, due to variations in the spring set load, lift of the valve body, and magnetic resistance, the valve opening delay Ta and valve closing delay Tb of the valve body 22 may be delayed. As a result, the valve body 22 does not open for a certain period of time. Conventionally, the dynamic flow rate was adjusted by finely adjusting the honeyset load. The dynamic flow rate can also be adjusted by this method as well. Therefore, in this embodiment, by gradually press-fitting the seat member 27 while measuring the dynamic flow rate, the lift amount of the valve body 22 is finely adjusted. This can be done by fixing the sheet member 27 to the housing 21 by caulking. Therefore, in this example,
In addition to the above-mentioned embodiments, dynamic flow rate adjustment can be performed using a sheet member, and an adjustment pipe can be omitted, so that the number of parts can be reduced.

(Effects of the Invention) As explained above, according to the first invention, the valve body is formed into a cylindrical shape, and the outer peripheral portion of the valve body is configured to slide within the guide hole, thereby eliminating the need for a conventional core. At the same time, it becomes possible to reduce the gap portion of the magnetic circuit to 1/1O or less of that of the conventional one, making it possible to manufacture the valve at low cost, and improving the responsiveness of the valve body as the magnetic resistance decreases. In addition, the flow can be adjusted either by static flow adjustment or by press-fitting the sheet member, making it easy to adjust the flow rate.
It is easy and can be carried out in a short time, eliminates the need for conventional lapping, etc., and reduces costs.

Further, according to the second aspect of the invention, dynamic flow rate adjustment can be performed by press-fitting the sheet member, and there is an advantage that an adjustment pipe can be eliminated and the number of parts can be reduced.

[Brief explanation of the drawing]

3 and 2 show an embodiment of the first invention, FIG. 1 is a longitudinal sectional view of a fuel injection valve, FIG. 2 is a characteristic diagram of static flow rate,
3 and 4 show an embodiment of the second invention, FIG. 3 is a vertical sectional view of the main part of the fuel injection valve, FIG. 4 is an explanatory diagram of the operation of the valve body, and FIG. 5 is a conventional fuel injection valve. FIG. 3 is a vertical cross-sectional view showing an injection valve. 21.21a...Housing and guide hole 22.2
2a, 26a...valve body, fuel passage and seat surface 23...connector pipes 27, 27a, 27b---seat member, seat portion and nozzle 29...electromagnetic coil 31...adjust pipe 3
2...Nozzle Spring Patent Applicant: Diesel Kiki Co., Ltd. Agent: Patent Attorney Masa Sumi Mori 0J 5s “Kokoro r'0

Claims (2)

[Claims] (1) An electromagnetic coil is arranged around a connector pipe fixed to the rear end side of the housing, and when the electromagnetic coil is energized, the valve is slidably inserted in the guide hole in the housing in the axial direction. In the fuel injection valve that lifts the body, the valve body is formed of a cylindrical magnetic material having a seat surface at its tip and a fuel passage inside, and the seat surface of the valve body is formed at the tip of the guide hole. A fuel injection valve characterized in that a seat member having a seat portion on which the fuel injection valve is seated and a nozzle port is press-fitted, and a nozzle spring is compressed between an adjustment pipe inserted into the connector pipe and the valve body. (2) An electromagnetic coil is arranged around a connector pipe fixed to the rear end side of the housing, and when the electromagnetic coil is energized, the valve is inserted into the guide hole in the housing so as to be slidable in the axial direction. In the fuel injection valve that lifts the body, the valve body is formed of a cylindrical magnetic material having a seat surface at its tip and a fuel passage inside, and the seat surface of the valve body is formed at the tip of the guide hole. A fuel injection valve characterized in that a seat member having a seat portion on which the fuel injection valve is seated and a nozzle port is press-fitted, and a nozzle spring is compressed between the connector pipe and the valve body.