JPH0192571A - Diaphragm type fuel pressure controlling valve - Google Patents

Abstract

PURPOSE:To provide high pressure regulating performance while improving assembling property by making a movable valve body of a ball held by a leaf spring to cause the ball to move toward and away from a valve seat by a holder provided on a diaphragm. CONSTITUTION:A combustion chamber 4 and an air chamber 5 are defined and formed by casing members 1, 2 and a diaphragm 3. The combustion chamber 4 is provided with an inlet path 6 and an outlet path 7, and an inlet leading from the combustion chamber 4 to the outlet path 7 is provided with a seat member 8. A ball 9 as a movable valve member is disposed opposedly to the seat member 8. The ball 9 is secured fixedly to a conical hole portion of a leaf spring 10 held by the casing member 1 by soldering, welding or the like. A holder 11 held together with a holding plate 12 on the center of diaphragm 3 abuts against said ball 9 to be urged and seated on the seat member 8 with a force of a spring 13.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a diaphragm type fuel pressure control valve used in a fuel injection device of an automobile gasoline engine, etc., and relates to a pressure control valve that controls fuel pressure almost constant. Regarding valves.

[Conventional technology]

In a fuel injection device for a spark-ignition internal combustion engine, it is important to maintain the fuel pressure almost constant in order to inject the amount of fuel that matches the operating conditions of the internal combustion engine, and the pressure used for this purpose is Control valves require high precision.

As for conventional pressure control valves, the structure shown in Fig. 7 as described in Patent Publication No. 49-37049 has been put into practical use, and the structure as shown in Fig. 4 as described in Utility Model Publication No. 1987-103863 has also been put into practical use. It has been devised.

[Problem that the invention seeks to solve]

In the above conventional technology, the valve seat and the movable valve body face each other with their flat parts, and when there is little fuel returning to the outlet passage, the end of the movable valve body comes into contact with the valve seat, and the end of the movable valve body comes into contact with the valve seat. Fuel will be discharged in the gap.

For this reason, there is a problem in that a sufficient function of the pressure control valve cannot be obtained in a flow rate range where only a small amount of fuel is discharged. Furthermore, metal materials are used because the two members collide when the valve is closed or when rapid pressure pulsations are applied to the seat portion.

Furthermore, the surface roughness of the seat surface is finished to be good in order to maintain the residual pressure in the fuel chamber when the valve is closed, which increases the manufacturing cost.

In view of the above, an object of the present invention is to use a diaphragm type seat that has a good pressure regulating function even in a low flow rate region where the amount of fuel discharged is small and is inexpensive to manufacture by configuring the seat part using a ball. An object of the present invention is to provide a fuel pressure control valve.

[Means for solving problems]

For the above purpose, the valve plate of the movable valve element has been abolished, and the valve seat is opened and closed using a ball, and the center point of the ball is always aligned with the axis of the valve seat, regardless of the amount of movement. This is achieved by supporting the ball to the casing member.

[Operation] The problem with supporting the ball to the casing member and opening and closing the valve seat lies in the structure that quickly transmits the movement of the diaphragm to the ball.

This problem can be solved by fixing the ball to a leaf spring and using the leaf spring to press the ball toward the diaphragm.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. A fuel chamber 4 and an air chamber 5 are defined by the casing members 1 and 2 and the diaphragm 3, and the fuel chamber 4 has an inlet passage 6 and an outlet passage 7, and a seat is provided at the inlet connecting the fuel chamber to the outlet passage. It has a member 8.

A ball 9 is arranged facing the sheet member 8. A leaf spring 1o is fixedly connected to the ball 9 by brazing, welding, etc., and the leaf spring 10 is supported by the casing member 1. Here, the ball 9 is accommodated in a conical hole formed by the leaf spring 10.

The ball 9 is in contact with the holder 11 of the diaphragm,
The inner periphery of the diaphragm 3 is sandwiched between the holding body 11 and the holding plate 12, and the diaphragm 3 is held airtight between the flange portion 1a of the casing member 1 and the intermediate plate 14 by caulking. . Reference numeral 13 is a spring for obtaining the required fuel pressure.

The present invention will be explained in detail below.

Fuel is introduced into the fuel chamber 4 from the inlet passage 6, and when the fuel pressure in the fuel chamber exceeds a predetermined value, the diaphragm 3 overcomes the force of the spring 14 and moves downward. Along with this movement, the ball 9 also moves downward and separates from the seat member 8, and the fuel flows into the outlet passage 7, controlling the fuel pressure in the fuel chamber 4 at a constant level.

Here, as shown in FIG. 3, fuel flows through at least one fuel passage 16 provided in the leaf spring 10. Furthermore, in FIG. 2, although not shown here, the casing member 1 may be provided with one or more holes penetrating from the fuel chamber 4 to the fuel passage 15 to allow fuel to flow therethrough.

Further, the plate spring 10 has a movement amount of 1.0 mm in the direction of the diaphragm.
The diameter of the ball 9 is several millimeters, and a biasing force is provided to keep the ball 9 in constant contact with the holder 11 of the diaphragm.

Next, when the fuel pressure in the fuel chamber 4 decreases and the force of the spring 13 becomes stronger, the ball 9 is quickly pressed against the seat member 8 by the diaphragm holder 11, and the fuel pressure in the fuel chamber 4 is maintained.

Here, the contact surface between the seat member 8 and the ball 9 is tapered, and when the valve is closed, the ball 9 is guided to reliably maintain fuel pressure. When assembling the valve part of this structure, the ball 9 and the leaf spring 10 are fixed, and while pressing the seat surface of the ball 9, which is a combination of two members, against the seat member 8, the leaf spring The outer periphery of 10 is connected to casing member 1
By coupling the seat member 8 to the ball 9, misalignment between the seat member 8 and the ball 9 can be prevented.

For this reason, a play of several millimeters is provided between the inner periphery of the leaf spring accommodating portion of the casing member and the outer periphery of the leaf spring 10. Needless to say, the axes of the center of the ball 9, the outer periphery of the leaf spring 1o, and the inner periphery of the leaf spring accommodating portion of the casing member are aligned to minimize the above-mentioned backlash.

〔Effect of the invention〕

According to the present invention, by sealing with the spherical surface of the ball, even when the flow rate of discharged fuel is small, the area of the fuel passage formed by the ball, which is a movable valve element, is stabilized, resulting in a good pressure regulating function. There is.

In addition, by supporting the ball toward the casing member and making it separate from the diaphragm holder, it is not affected by diaphragm misalignment or unbalanced spring load during assembly, so the seat member and movable valve body can be separated. It has the advantage of being easy to assemble, since the ball doesn't come into contact with the center of the ball.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of a diaphragm type fuel pressure control valve according to an embodiment of the present invention, Fig. 2 is an enlarged view of the seat portion of Fig. 1, and Fig. 3 is a shape diagram of Fig. 2 seen from below. , FIG. 4 and FIG. 7 are vertical sectional views of a conventional diaphragm type fuel pressure control valve, FIG. 5 is an enlarged view of the seat portion of FIG. 4, and FIG.
FIG. 8 is an enlarged view of the seat portion of FIG. 7.

Claims (1)

[Claims] 1. A diaphragm type in which a fuel chamber and an air chamber are defined by a casing and a diaphragm, a valve seat is provided in the outlet passage of the fuel chamber, and the valve seat is opened and closed by a movable valve body that operates in unison with the diaphragm. In the fuel pressure control valve, a holding body that holds the diaphragm opens and closes the valve seat via a ball that is the movable valve body, and the ball is held in the casing by a support, and the support A diaphragm type fuel pressure control valve characterized in that it is a leaf spring fixed to the ball.