JP2000145588A - Variable nozzle hole type fuel injection nozzle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the short-time installation of actuators for displacing or rotating rotary valves. SOLUTION: A direct-operated solenoid actuator 21 is mounted on the upper end of a nozzle holder 2 so that its output shaft 21a is inserted down in a slide hole 2a wherein a movable member 23 is inserted slidably but immovably. The movable member 23 has in its lower end face a hole 23a wherein the upper end of a rotary shaft 10 is inserted vertically movably and rotatably. The hole 23a has in its inner surface a spiral cam groove 23b extending up from the lower opening thereof. The rotary shaft 10 has in its outer surface a cam portion 10a fitting slidably in the cam groove 23b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable injection hole type fuel injection nozzle in which the exposed area of an opening on the inner surface of a nozzle body of an injection hole (referred to as an opening area in this specification) is variable.

[0002]

2. Description of the Related Art Generally, a variable injection hole type fuel injection nozzle is
A rotary valve is rotatably provided inside the nozzle body, and the rotary valve is rotationally displaced via a rotary shaft by a rotary actuator such as a stepping motor. Thus, the opening area of the injection hole is changed (Japanese Patent Laid-Open No. 9-280134).
Reference).

[0003]

In the above-mentioned conventional fuel injection nozzle, it is necessary to make the axis of the output shaft of the rotary actuator exactly coincide with the axis of the rotary shaft. Otherwise, the rotation of the rotary actuator cannot be accurately transmitted to the rotary shaft and thus to the rotary valve. However, it is very difficult to exactly match the axis of the output shaft with the axis of the rotary shaft. For this reason, there has been a problem that much labor and time are required for mounting the rotary actuator.

[0004]

According to a first aspect of the present invention, there is provided a nozzle body having an injection hole, rotatably fitted inside the nozzle body, and positioned at a rotational position. A rotary valve that changes the opening area of the injection hole on the inner surface of the nozzle body in accordance with the rotation of the rotary valve via a rotary shaft that is rotatably and fixedly disposed inside the nozzle body. In the variable injection hole type fuel injection nozzle provided with a displacement means, the rotational displacement means comprises: a direct-acting actuator for linearly moving an output shaft; and a gap between a facing surface of the output shaft of the direct-acting actuator and the rotary shaft. Is arranged so as to be movable in the axial direction of the rotary shaft and non-rotatable, and is biased by an urging means to the output shaft of the direct acting actuator. And a transmission mechanism that converts linear movement of the movable member into rotation and transmits the rotation to the rotary shaft is provided between the movable member and the rotary shaft. It is characterized by. In this case, one of the movable member and the rotary shaft is provided with a cylindrical portion, and the other is provided with a shaft portion that is movably inserted into the cylindrical portion. A positive cam comprising a helically extending cam groove provided on one of the peripheral surface and the outer peripheral surface of the shaft portion, and a cam portion provided on the other and slidably fitted in the cam groove. A mechanism is desirable. It is preferable that the cylinder is provided on the movable member, and that the urging means be disposed between the bottom of the cylinder and the rotary shaft fitted to the cylinder. It is desirable that the rotary shaft be formed integrally with the rotary valve.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. 1 and 2 are views showing an embodiment of a variable injection hole type fuel injection 1 according to the present invention. FIG. 1 is a cross-sectional view showing the entire configuration, and FIG.
FIG. 2 is an enlarged view of an X circle portion in FIG. 1.

As shown in FIG. 1, a fuel injection nozzle 1 is
It has a vertically long nozzle holder 2. A nozzle body 3 is pressed and fixed to a lower end surface of the nozzle holder 2 by a nozzle nut 4 via a spacer 5. The nozzle main body 3 is formed with a valve receiving hole 3a extending from the upper end surface to the vicinity of the lower end thereof. As shown in FIG. It is formed on the core. A plurality of injection holes 3c are opened on the inner peripheral surface of the tapered hole 3b. Each injection hole 3c is provided in the nozzle body 3
Are arranged at the same position in the axial direction and at equal intervals in the circumferential direction.

A needle valve (valve element) 6 is slidably inserted into the valve receiving hole 3a. The needle valve 6 is urged downward by a nozzle spring 7 housed in the lower end of the nozzle holder 2 and has a tapered hole 3b slightly above the injection hole 3c.
It is designed to be seated on the inner peripheral surface. The place where the needle valve 6 is seated is the valve seat 3d.

When the fuel is pumped from the fuel injection pump (not shown) to the fuel reservoir 3e via the fuel passage 8 and the pressure of the pumped fuel becomes equal to or higher than a predetermined valve opening pressure, the needle valve 6 operates. Lift from the valve seat 3d against the urging force of the nozzle spring 7. Then, the fuel pumped to the fuel reservoir 3e is injected from the injection hole 3c. When pumping of fuel is interrupted,
The needle valve 6 is seated on the valve seat 3 d by the urging force of the nozzle spring 7. Thereby, one fuel injection is completed.

As shown in FIG. 2, a rotary valve 9 is rotatably fitted to the bottom side of the tapered hole 3b. Therefore, the outer peripheral surface of the rotary valve 9
The valve seat 3 has the same taper angle as the tapered hole 3b.
d also has the same taper angle. However, the outer peripheral surface of the rotary valve 9 and the nozzle body 3 to which it is fitted
May have a taper angle different from that of the valve seat 3d, or may have a straight hole shape.

The outer peripheral surface of the rotary valve 9 is formed with the same number of communication grooves 9a as the number of the injection holes 3c extending downward from the upper end thereof. Each communication groove 9a is arranged at substantially the same position as the injection hole 3c in the vertical direction and at equal intervals in the circumferential direction. In addition, the width of the communication groove 9a in the circumferential direction of the rotary valve 9 and the two communication grooves 9
The interval between a and 9a is almost the same as or slightly larger than the inner diameter of the injection hole 3c. Therefore, by appropriately adjusting the rotational position of the rotary valve 9, the opening inside the injection hole 3c (the opening on the inner peripheral surface of the tapered hole 3b) can be removed.
It can be opened to the fuel reservoir 3e side through the communication groove 9a, and the opening area of the opening inside the injection hole 3c, that is, the opening area is changed from the state where the entire inside opening is opened to the state where the entire opening is rotary. It can be changed to a state where it is shielded by the valve 9.

The needle valve 6 has a through hole 6a penetrating the axis from the upper end surface to the lower end surface. The rotary shaft 10 is inserted through the through hole 6a so as to be rotatable and relatively movable up and down. The lower end of the rotary shaft 10 is
And are integrally connected. In other words, the rotary shaft 10 is formed integrally with the rotary valve 9.

Here, when the rotary shaft 10 is formed integrally with the rotary valve 9, the tapered hole 3d and the through hole 6a are formed due to a manufacturing error of each part related thereto.
It is slightly eccentric. For this reason, the rotary valve 9 is fitted into the tapered hole 3b,
When 0 is fitted into the through hole 6a, the rotary shaft 10 is bent by the amount of eccentricity between the tapered hole portion 3d and the through hole 6a. As a result, smooth rotation of the rotary shaft 10 and relative movement with respect to the needle valve 6 in the up-down direction may be hindered. Therefore, as shown in FIG. 2, the lower part of the through hole 6a is made larger in diameter than the rotary shaft 10, and only the upper end of the through hole 6a is made the rotary shaft 1
0 without any gap. By doing so, the distance from the fitting portion of the rotary shaft 10 to the through hole 6a to the rotary valve 9 becomes longer, and the amount of bending of the rotary shaft 10 per unit length with respect to a certain amount of eccentricity becomes smaller. Therefore, the rotary shaft 10
And the vertical movement with respect to the needle valve 6 can be performed smoothly. Moreover, the fitting of the rotary shaft 10 and the upper end of the through hole 6a can prevent fuel from leaking from between them.

As shown in FIG. 1, a sliding hole 2a extending downward is formed in the upper end surface of the nozzle holder 2. The upper portion of the rotary shaft 10 enters the sliding hole 2a. Although the sliding hole 2a and the rotary shaft 10 are concentric in design, they are slightly eccentric due to a manufacturing error of each part related thereto. The rotary shaft 10 penetrates the lower part and the central part of the spring receiver 11 and the nozzle holder 2, and a slight gap is formed between each part penetrating and the rotary shaft 10.

The upper end of the rotary shaft 10 that has entered the sliding hole 2a is rotationally displaced by the rotational displacement means 20. This rotational displacement means 2
0 is configured as follows.

That is, at the upper end of the nozzle holder 2,
Electromagnetic actuator 21 as direct acting actuator
Are fixed by a nut 22. The electromagnetic actuator 21 linearly moves the output shaft 21a forward and backward. The position of the output shaft 21a is determined according to the magnitude of the voltage or current applied to a built-in solenoid (not shown). It is determined. The output shaft 21a is inserted into the slide hole 2a with its tip end facing downward and facing the upper end surface of the rotary shaft 10.

A movable member 23 is slidably and non-rotatably inserted into the sliding hole 2a. This movable member 23
Is pressed against the distal end surface of the output shaft 21a by a return spring (biasing means) 24 disposed between the lower end surface and the bottom surface of the slide hole 2a. Therefore, the movable member 2
Reference numeral 3 follows the linear movement of the output shaft 21a and moves integrally therewith.

A guide hole 23a extending from the lower end surface to the vicinity of the upper end is formed inside the movable member 23.
The portion where the guide hole 23a is formed is a cylindrical portion 23A. The guide hole 23a is formed so that its axis coincides with the axis of the rotary shaft 10, and the upper end of the rotary shaft 10 is rotatably and vertically inserted therein. The portion of the rotary shaft 10 inserted into the guide hole 23a is the shaft portion 10A. It is desirable that the inner diameter of the guide hole 23a and the outer diameter of the shaft portion 10A be the same as much as possible within a range that allows rotation and vertical movement of the shaft portion 10A.

A compression spring (biasing means) 25 is disposed between the bottom surface of the guide hole 23a and the upper end surface of the shaft 10A. This spring 25 urges the movable member 23 upward,
The upper end surface is pressed against the lower end surface of the output shaft 21a.
Therefore, the return spring 24 is not always necessary and can be omitted. By omitting the return spring 24 and disposing the spring 25 in the guide hole 23a, the size of the fuel injection nozzle 1 can be reduced. Further, the spring 25 urges the rotary shaft 10 downward, and presses the rotary valve 9 against the tapered surface 2b. As a result, the positions of the rotary valve 9 and the rotary shaft 10 are fixed.

On the inner peripheral surface of the guide hole 23a, a cam groove 23b extending spirally from the lower end opening is formed. On the other hand, a cam portion 10a is formed on the outer peripheral surface of the shaft portion 10A. The cam portion 10a is formed as a part in the longitudinal direction of a ridge having substantially the same cross-sectional shape as the cam groove 23b, but may be formed as a long ridge. The cam portion 10a is slidably fitted in the cam groove 22b along the spiral thereof, and the cam portion 10a and the cam groove 22b constitute a positive cam mechanism (transmission mechanism) 26.

Therefore, when the output shaft 21a of the electromagnetic actuator 21 is moved up and down, the movable member 23 is moved up and down following the movement, and the rotary shaft 10 and the rotary valve 9 are rotationally displaced in the forward and reverse directions. Thereby, the opening area of the injection hole 3c is changed.
When the output shaft 21 is stopped, the movable member 23 stops, and the rotary shaft 10 and the rotary valve 9 stop. Thereby, the opening area of the injection hole 3c is kept constant.

In the fuel injection nozzle 1 having the above structure,
Since the direct-acting actuator 21 only pushes the movable member 23 downward by a unit, it is not necessary to make the axis of the output shaft 21 a exactly coincide with the axis of the rotary shaft 10. Therefore, the electromagnetic actuator 21 can be easily attached in a short time.

FIG. 3 shows another embodiment of the present invention. In a fuel injection nozzle 1 'of this embodiment, a cylinder mechanism 30 is used as a direct-acting actuator.
Is used. The cylinder mechanism 30 uses the upper end of the sliding hole 2 a as a cylinder hole, and the upper end of the sliding hole 2 a is closed by a lid 31. A piston (output shaft) 32 is slidably provided in the sliding hole 2a below the lid 31. A cylinder chamber 33 is provided between the piston 32 and the lid 31. The cylinder chamber 33 has a switching state that is closed by a switching valve 34 to the outside, and an opening state that is connected to a pump 35. The state can be switched to a return state connected to the fuel tank 36. The movable member 23 is pressed against the lower end surface of the piston 32 by springs 24 and 25.
Therefore, the movable member 23 moves up and down following the piston 32. In addition, although the torsional direction of the cam groove 23a is opposite to that of the above-described embodiment, it may be the same direction.

In the fuel injection nozzle 1 'having the above structure,
When the cylinder chamber 33 is connected to the pump 35, the piston 3
2 and the movable member 23 move downward against the urging force of the springs 24 and 25, and the rotary valve 9 is rotationally displaced in one direction. When the cylinder chamber 33 is connected to the fuel tank 36, the piston 32 and the movable member 32
, The rotary valve 9 is rotationally displaced in the other direction. When the switching valve 34 is closed, the piston 32 and the movable member 23 stop, and the rotary valve 9 stops.

In the fuel injection nozzle 1 ', since the cylinder mechanism 30 is used as a direct-acting actuator, the stroke of the movable member 23 can be made larger than when the electromagnetic actuator 21 is used. When the stroke of the movable member 23 is increased, the lead of the cam groove 23a for rotating the rotary valve 9 by a fixed amount can be increased, so that the rotational position control accuracy of the rotary valve 9 can be improved.

It should be noted that the present invention is not limited to the above-described embodiment, and can be appropriately changed. For example, in the above-described embodiment, the cylindrical portion 2
3A, and the shaft 1
Although 0A is formed, a cylindrical portion having an upper end opened at the upper portion of the rotary shaft 10 may be formed, and a shaft portion inserted into the cylindrical portion from the upper end opening may be formed at the lower portion of the movable member. . Further, the cam groove 23b is formed on the inner peripheral surface of the cylindrical portion 23A, and the cam portion 10a is formed on the outer peripheral surface of the shaft portion 10A. 1
A cam groove may be formed on the outer peripheral surface of 0A. Moreover, the cylinder part 2
It is possible to provide a ball screw mechanism between 3A and the shaft part 10, and to use this ball screw mechanism as a positive cam mechanism.

[0026]

As described above, according to the present invention, even if the mounting accuracy of the direct-acting actuator is low, it does not matter at all, so that the direct-acting actuator can be mounted easily and in a short time. The effect is obtained. Further, by providing a cylinder portion on the movable member and disposing an urging means for pressing the movable member against the output shaft of the direct-acting actuator in the cylinder portion, the size of the fuel injection nozzle can be reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention.

FIG. 2 is an enlarged view of an X circle portion in FIG.

FIG. 3 is a partially omitted longitudinal sectional view of another embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 variable injection hole type fuel injection nozzle 1 ′ variable injection hole type fuel injection nozzle 3 nozzle body 3 c injection hole 9 rotary valve 10 rotary shaft 10 A shaft portion 10 a cam portion 20 rotational displacement means 21 electromagnetic actuator (direct-acting actuator) 23 movable Member 23A Cylindrical portion 23b Cam groove 24 Return spring (biasing means) 25 Spring (biasing means) 26 Positive cam mechanism (transmission mechanism) 30 Cylinder mechanism (linear actuator) 32 Piston (output shaft)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshiyuki Hasegawa 3--13-26 Yayumicho, Higashimatsuyama-shi, Saitama Prefecture Inside of Xexel Higashi-Matsuyama Plant (72) Inventor Hayato Maehara 3--13, Yayumicho, Higashimatsuyama-shi, Saitama No. 26 F-term in Zexel Higashi-Matsuyama Plant (reference) 3G066 BA56 BA67 CC05T CC05U CC06T CC18 CC23 CC26 CE13 CE22 CE34

Claims (4)

[Claims] 1. A nozzle body having an injection hole, a rotary valve rotatably fitted inside the nozzle body, and changing an opening area of the injection hole on an inner surface of the nozzle body according to a rotation position. Rotary displacement means for rotatably displacing the rotary valve inside the nozzle body, and rotationally displaced via a rotary shaft arranged in a fixed position, the variable injection hole type fuel injection nozzle, wherein the rotational displacement means, A linear actuator for linearly moving the output shaft; and a linearly movable non-rotatably disposed between the output shaft of the linear actuator and the opposed surface of the rotary shaft in the axial direction of the rotary shaft. A movable member pressed by an urging means against an output shaft of a dynamic actuator, wherein the movable member and the rotary Between the shaft, a variable injection hole type fuel injection nozzle, wherein a transmission mechanism for transmitting the rotary shaft converts the linear movement of the movable member to rotate is provided. 2. A cylinder part is provided on one of the movable member and the rotary shaft, and a shaft part movably inserted into the cylinder part is provided on the other, and the transmission mechanism is provided on the cylinder part. A spirally extending cam groove provided on one of the inner peripheral surface of the shaft and the outer peripheral surface of the shaft portion, and a cam portion provided on the other and slidably fitted in the cam groove. 2. The variable injection hole type fuel injection nozzle according to claim 1, wherein the nozzle is a moving cam mechanism. 3. The method according to claim 1, wherein the cylinder is provided on the movable member, and the urging means is disposed between a bottom of the cylinder and the rotary shaft fitted to the cylinder. The variable injection hole type fuel injection nozzle according to claim 2. 4. The variable injection hole type fuel injection nozzle according to claim 3, wherein the rotary shaft is formed integrally with the rotary valve.