JP2009167924A - Injector - Google Patents

Abstract

A normally closed injector that supports a valve element with a plate-shaped valve spring can easily achieve high fuel metering accuracy.
In an electromagnetically driven injector 1A in which a valve body 4A and a movable iron core 2c are supported by a plate-shaped valve spring 5 and are energized in a valve closing direction to maintain the valve closed state when not energized. A coil-shaped second valve spring 6 that biases 4A in the valve closing direction is provided, and the two valve springs 5 and 6 cooperate with each other to act on the valve body 4A with a double spring load. A spring pressure displacement screw 7 is provided as a spring load adjustment mechanism for adjusting the spring load of the second valve spring 6 from the outside. By operating the spring pressure displacement screw 7 from the outside, the valve body is provided. The spring load that finally acts on 4A can be adjusted and set.
[Selection] Figure 1

Description

  The present invention relates to an electromagnetically driven injector for injecting fuel of a flow rate required by an engine, and in particular, a valve body of an on-off valve (fuel metering valve) is supported by a plate-like valve spring central portion. The present invention relates to a normally closed injector that is closed by being pressed against a valve seat by a spring load of a valve spring.

  An electromagnetically driven injector that opens an on-off valve by attracting a movable iron core by energizing and exciting an electromagnetic coil is described in, for example, Japanese Utility Model Laid-Open No. 61-105756, as shown in FIG. As shown in the longitudinal sectional partial view, the valve body 4B of the on-off valve is supported (held) by a plate-like valve spring 5, and the sealing surface is pressed against the valve seat of the seat member 3 to maintain the valve closed state. A normally closed injector 1B is known. The valve spring 5 is formed by forming a thin metal plate into a disk shape as shown in the plan view of FIG.

  The injector 1B having such a configuration is generally called a hold-type injector, and has wear durability when using a gas fuel that cannot use fuel as a lubricant in a plunger-type injector that slides a movable iron core. Although the problem has occurred, as shown in the exploded view of FIG. 2C, the valve body 4B is floated and held by the valve spring 5, so that the sliding of the movable core 2c or the valve body 4B with respect to the fixed core 2e. There is no moving part, and there is an advantage that the problem of wear durability hardly occurs.

  However, since the hold type injector 1B has a configuration in which the spring load is determined by a combination of component dimensions, the fuel metering accuracy has a characteristic that it is greatly affected by variations in component assembly. That is, as shown in the enlarged partial view of FIG. 3, the valve spring 5 in a state where the valve body 4 </ b> B is pressed against the valve seat of the seat member 3 when the end edge side of the valve spring 5 is fixed when the injector body is assembled. The fuel metering accuracy is determined by the spring load due to the deformation amount.

For this reason, the dimensional error of each component and the slight error in assembly greatly affect the fuel metering accuracy. In such a hold-type injector 1A, the fuel metering accuracy between finished products greatly varies. There is a problem that it is likely to be difficult and it is difficult to achieve high fuel metering accuracy.
Japanese Utility Model Publication No. 61-105756

  SUMMARY OF THE INVENTION The present invention is intended to solve the above-described problems, and it is possible to easily realize high fuel metering accuracy for a normally closed injector that supports a valve body with a plate-shaped valve spring. Is an issue.

  Therefore, the present invention provides an electromagnetically driven injector in which a valve body and a movable iron core are supported by a plate-shaped valve spring and are energized in the valve closing direction to maintain the valve closed state when not energized. A coil-shaped second valve spring that biases in the valve direction is provided, and the two valve springs cooperate to act on the valve body with a double spring load. The second valve spring A spring load adjustment mechanism for adjusting the spring load of the valve body from the outside is provided. By operating the spring load adjustment mechanism from the outside, the spring load that finally acts on the valve body can be adjusted and set.

  As described above, the coil-shaped second valve spring is arranged in addition to the plate-shaped first valve spring, and the spring load of the second valve spring can be adjusted from the outside, so that it is desirable after assembly of the injector. Therefore, even if there is a variation in the dimensional accuracy and assembly state of each part, it is easy to ensure high fuel metering accuracy evenly.

  In this case, the spring load adjustment mechanism includes a second valve spring in which a coil-shaped second valve spring is inserted along a central axis of a through hole that passes through the central axis of the fixed iron core. A substantially cylindrical slide member is screwed on the base end side, and the second valve spring is sandwiched between the movable iron core in a compressed state, and the through-hole is formed while rotating the slide member from the outside in a screw manner. If the compression width of the second valve spring is changed and adjusted and set to a desired spring load by sliding the inside, setting of the spring load is extremely easy and Fine adjustment is also easy.

  According to the present invention in which the coil-shaped second valve spring is provided in addition to the plate-shaped first valve spring in a state in which the spring pressure can be adjusted from the outside, high fuel metering accuracy can be easily realized.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 (A) shows a longitudinal sectional partial view centering on an opening / closing valve portion of an injector 1A according to an embodiment of the present invention. The injector 1A is an electromagnetically driven injector (fuel injection valve) including an electromagnetic coil 2a, a fixed iron core 2b, and a movable iron core 2c, and a valve body 4A is provided on the lower side (downstream side) of the movable iron core 2c. These are so-called hold-type injectors supported by a valve spring 5 which is a circular / plate-shaped leaf spring provided at a right angle to the valve stroke direction.

  Further, a cylindrical seat member 3 constituting a valve seat is disposed below the valve body 4A to constitute an on-off valve, and the sealing surface of the valve body 4A is in close contact with the valve seat of the seat member 3 When the valve is closed, the valve spring 5 is in a state where the central portion is lifted slightly upward and elastically deformed in a convex shape, and a spring load in the valve closing direction is generated by the elastic repulsive force. The components described above are substantially the same as the conventional injector 1B shown in FIG.

  As shown in the exploded view of the valve structure portion in FIG. 1B, a coiled valve spring 6 as a second valve spring is provided along the valve stroke direction at a substantially central portion of the upper surface of the movable iron core 2c. The valve body 4A of the on-off valve is disposed in a vertically compressed state so as to urge the valve body 4A in the valve closing direction. The valve body 4A is closed in cooperation with the first valve spring 5 described above. The valve is biased in the direction of the valve, and the spring load acts twice.

  Further, in the present embodiment, the spring displacement screw 7 constituting a part of the spring load adjusting mechanism capable of adjusting the spring load from the outside penetrates a part of the outer peripheral surface and the center of the fixed iron core 2b. A screw structure is formed with a part of the inner peripheral surface of the hole 20 and is screwed into the through hole 20, and is arranged as a slide member that slides by rotating in a screw manner. The spring 6 is in close contact with the proximal end side and is sandwiched between the movable iron core 2c in a compressed state.

  The injector 1A having such a configuration is configured such that the spring displacement screw 7 is rotated from the outside by using a screwdriver or the like from the outside of the opposite end of the valve mechanism portion, so that the spring displacement screw is inserted in the through hole 20 of the fixed iron core 2b. 7 can be slid along the valve stroke direction (coincident with the central axis of the through-hole 20) and fixed at a desired position, and between the distal end side of the spring displacement screw 7 and the proximal end side of the movable iron core 2c. The coiled valve spring 6 sandwiched between the two can be set to a desired compression width, and its spring pressure can be adjusted and set to a desired level, which is a feature of the present invention.

  As a result, the load on the plate-like first valve spring 5 can be reduced as compared with the case of the conventional injector 1B, and the reduced load can be applied to the coil-like second valve spring 6. In addition, by adjusting the spring pressure of the valve spring 6 by operating the spring displacement screw 7 from the outside after the assembly of the injector 1A, the final spring pressure applied to the valve body 4A can be easily set to a desired state. Can do.

  Accordingly, in the conventional type injector 1B, the spring load of the valve spring 5 is greatly fluctuated due to slight dimensional errors of parts and slight assembly variations, and it becomes difficult to achieve high flow rate adjustment accuracy, and there is also variation between products. In this embodiment, the final spring load can be easily adjusted from the outside, although it was easy to increase, high flow rate adjustment accuracy can be easily realized, and variation between products can be reduced. Can do.

  As described above, according to the present invention, high fuel metering accuracy can be easily realized for a normally closed injector that supports a valve element with a plate-shaped valve spring.

(A) is a longitudinal cross-sectional partial view centering on the valve mechanism part of the injector of embodiment of this invention, (B) is an exploded view of the valve structure part of the injector of (A). (A) is a longitudinal sectional partial view centering on the valve mechanism portion of the injector in the conventional example, (B) is a plan view of the valve spring of the injector of (A), and (C) is a valve structure portion of the injector of (A). Exploded view. FIG. 3 is an enlarged partial view of a valve structure portion of the injector of FIG. 2.

Explanation of symbols

1A Injector, 2a coil, 2b Fixed iron core, 2c Movable iron core, 3 Seat member, 4A Valve body 4A, 6 Valve spring, 7 Spring pressure displacement screw, 20 Through hole

Claims (2)

  In an electromagnetically driven injector in which the valve body and the movable iron core are supported by a plate-shaped valve spring and are energized in the valve closing direction and maintain the valve closed state when not energized, the valve element is energized in the valve closing direction. A coiled second valve spring is provided, the two valve springs cooperate to act on the valve body with a double spring load, and the spring load of the second valve spring is externally applied. An injector comprising a spring load adjusting mechanism for adjusting, and by adjusting the spring load adjusting mechanism from the outside, the spring load that finally acts on the valve body can be adjusted and set. . The spring load adjusting mechanism includes a through-hole penetrating the central axis of the fixed iron core, the second valve spring being inserted along the central axis, and a substantially cylindrical shape on the proximal side of the valve spring. A slide member is screwed and the second valve spring is compressed and sandwiched between the movable iron core and is slid in the through-hole while rotating the slide member from the outside in a screw manner. Accordingly, the compression width of the second valve spring is changed and adjusted and set to a desired spring load.

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