JPS629075A - Piezo-electric control valve - Google Patents

Abstract

PURPOSE:To miniaturize the spreading mechanism for the displacement of a piezo-electric element, by successively pressing laterally lined plural spreading levers in the point end of the spreading lever in the preceding stage and spreading the displacement. CONSTITUTION:Plural spreading levers 1, 2, 3 are turnably supported by supporting axes (a), (b). While the spreading levers 1, 2, 3, facing their free end to the other supporting axis, respectively provide pins 1p, 2p in the lateral direction from the other supporting axis to this side position. Further the spreading lever 3 provides a slit 13 for mounting a valve shaft. While the pin 1p of the spreading lever 1 is adapted to and engaged with the upper to a rotatably supporting part of the spreading lever 2, and the pin 2p of the spreading lever 2 is adapted to the upper of a position to a rotatably supporting part of the spreading lever 3. And the displacement part of a piezo-electric element is adapted to the upper of a position 12 to a rotatably supporting part of the spreading lever 1. By this constitution, a spreading mechanism can be formed in a small size.

Description

[Detailed Description of the Invention] [Summary] Two support shafts are arranged parallel to each other with an interval, and at least two enlarged levers are arranged parallel to each other, and adjacent enlarged levers are alternately provided with different supports. It is supported on a shaft, and the tip is directed toward the other support shaft, and the position of each expansion lever near the free end displaces the position of the expansion lever of the next stage adjacent to the shaft, and the expansion of the last stage is performed. By applying driving force to the valve body using a lever and applying force due to the displacement of the piezoelectric element to the position near the shaft of the first stage expansion lever, it is possible to magnify the minute displacement of the piezoelectric element and drive the valve body. do.

[Industrial application field]

In a valve device that requires high-speed operation, such as a fuel injection valve for an internal combustion engine, a configuration has been proposed in which a valve body is driven by applying a signal voltage to a piezoelectric element to deform it. The present invention relates to a piezoelectric control valve that uses a piezoelectric element to drive a valve body.

[Conventional technology]

As described in Japanese Patent Publication No. 49-6043, etc., using the displacement when voltage is applied to a piezoelectric element,
It has been proposed to drive fuel injection valves and the like. When using a piezoelectric element as a drive source in this way, the amount of displacement of the piezoelectric element alone is insufficient for the amount of displacement of the valve body.
Various mechanisms have been attempted to increase the amount of displacement of piezoelectric elements. For example, lever type, link type, hydraulic type, etc. have been proposed. Among them, the lever type is mechanically the simplest,
It is also easy to manufacture.

FIG. 2(a) is an example of a lever type, in which the fulcrum of one lever 4 is fixed, and a piezoelectric element 9 is connected at a position near the fulcrum.
The free end drives the valve body. The amount of displacement of the piezoelectric element 9 is ΔX,
Assuming that the length from the fulcrum to the point of action of the piezoelectric element 9 is 1 and the lever ratio is 1:n, a displacement amount of nΔX is obtained at the free end.

This lever-type enlarging mechanism is stacked in two stages as shown in (B), and the free end of the lever 4a in the first stage displaces the position near the fulcrum of the lever 4b in the second stage above it. When the valve body is driven with the free end of the eye lever, a displacement amount of n2ΔX is obtained.

[Problem that the invention seeks to solve]

However, in such an expanding mechanism, as the amount of displacement is expanded, the space in the displacement direction becomes larger, and especially when trying to obtain a large amount of displacement using a multi-stage system, it is difficult to use the lever 4a.
, 4b in the displacement direction must be increased, resulting in a large-sized device. The technical problem of the present invention is
Solving these problems with conventional piezoelectric control valves,
The object of the present invention is to miniaturize a mechanism for enlarging the displacement of a piezoelectric element.

[Means for solving problems]

FIG. 1 is a perspective view illustrating the basic principle of a piezoelectric control valve according to the present invention. aSb are supporting shafts, which are arranged parallel to each other. Both support shafts a1b have a plurality of enlarged levers, that is, a first enlarged lever 1, a second enlarged lever 2,
A third enlarged lever 3 is pivotally supported. 1st expansion lever 1
is supported by the first support shaft a, the second enlarged lever 2 is supported by the second support shaft, and the third enlarged lever 3 is supported by the first support shaft a. The free end of each expansion lever 1.2.3 is directed toward the other support shaft, and each has horizontal pins 1p and 2p at a position in front of the other support shaft. The lever 3 is provided with a slit 13 for attaching the valve stem. The pin 1p of the first enlarged lever 1 abuts and engages the second enlarged lever 2 near the pivot part, and the pin 2p of the second enlarged lever 2 comes near the pivot part of the third enlarged lever 3. It is in contact with the position above. Then, the displacement portion of the piezoelectric element is brought into contact with a position 12 near the shaft portion of the first enlarged lever 1.

[Effect]

The pin position of each enlarged lever 1.2.3 is located closer to its own shaft than the other shaft. Therefore, when a force due to the displacement of the piezoelectric element is applied to the point of action near the shaft of the first expansion lever 1, the amount of displacement of the pin position at the tip of the expansion lever 1 is expanded, and the next expansion lever 2 is moved. The enlarged lever 2 is rotated by pressing the position near the shaft support. Then, the amount of displacement of the position of the pin 2p of the second enlarged lever 2 is further enlarged, and in order to press and rotate the position near the shaft support of the final stage enlargement lever 3, the output part (slit The displacement amount of 13) is further expanded. If expressed using the formula of the conventional lever-type enlarging mechanism shown in FIG. 2, the enlargement ratio will be n3ΔX times.

〔Example〕

Next, examples will be used to explain how the piezoelectric control valve according to the present invention is actually implemented. 3 and 4 are views showing an embodiment of the piezoelectric control valve according to the present invention, FIG. 4 is a sectional view taken along line IV-IV in FIG. 3, and FIG. 3 is a front view showing the inside of the enlarged part casing. It is. 5 is an enlarged part casing;
Support shafts a and b are internally supported at positions near the bottom, and three enlarged levers 1.2.3 are pivotally supported on the support shaft asb. Reference numeral 6 denotes a nozzle part main body, to which a nozzle cap 8 containing a nozzle needle 7 and a set screw 10 of a piezoelectric element 9 are attached, as well as an enlarged part casing 5.
It also serves as a lid.

A first enlarged lever 1 and a third enlarged lever 3 are rotatably supported on the support shaft a, and a second enlarged lever 2 is disposed between the re-enlarged levers 1 and 3. It is rotatably supported on a shaft. A spherical pressurizing semicircular base 11 at the tip of the piezoelectric element 9 is fitted into a spherical recess 12 at a position closer to the spindle a of the first enlarged lever 1. Also, in the slit 13 at the free end of the final stage enlargement lever 3, a small diameter neck portion 7a at the rear end of the nozzle needle 7 is inserted.
When the expansion lever 3 moves in the direction of the arrow a1, the nozzle needle 7 is pulled in the direction of the arrow a1 via the head portion 7b.

The nozzle needle 7 is normally connected to the nozzle 1 by a spring 14.
The nozzle 15 is pressed in five directions and the needle part 7C at the tip
is closed.

The inside of the nozzle cap 8 communicates with the inlet 16,
A fluid source is connected to the inlet 16. Therefore, when the needle portion 7c retreats to open the nozzle 15, fluid is ejected from the nozzle 15. Note that 17 and 18 are O-rings for sealing. Also, one end of the spring 14 for closing the nozzle is 0.
It abuts on a flat washer 19 on the ring 17, and the other end abuts on a flat washer 21 on the E washer 20.

The nozzle main body 6 is fixedly attached to the enlarged part casing 5 with screws 22, and the casing 5 has an enlarged mechanism built therein.
will be closed.

[Operation explanation]

Usually, a spring 14 causes the nozzle needle 7 to
The nozzle 15 is closed by being pressed in the direction of arrow a2. Now, when a driving voltage of 100V to 200VDC is applied to the lead wire 23, the piezoelectric element 9 expands, and the pressing half-round base 11 at the tip is displaced in the direction of the arrow a1, and the first enlargement lever 1
The first enlarged lever 1 is rotated in the direction of the arrow a1 about the supporting shaft a. As a result, the first
The amount of displacement at the position of the pin 1p at the tip of the enlarged lever 1 is expanded, and the pin 1p presses the position near the spindle of the enlarged lever 2 at the next stage, expanding the amount of displacement at the position of the pin 2p at the tip. . Then, the final stage enlarged lever 3 is rotated around the support shaft a by the pin 2p, and the head 7b at the rear end of the nozzle needle 7 is pulled in the direction of the arrow a1 by the slit 13 at the tip. Then, the nozzle needle 7 moves in the direction of the arrow a1 against the spring 14, the needle portion 7C at the tip moves away from the nozzle 15, the nozzle 15 is opened, and the fluid that has flowed in from the inlet 16 is jetted out from the nozzle 15. .

In the illustrated example, the lever ratio of each of the enlargement levers 1, 2, and 3 is approximately 1:5, so the amount of displacement of the piezoelectric element 9 is expanded 125 times at the slit 13 position of the enlargement lever 3 at the final stage. .

〔Effect of the invention〕

As described above, according to the present invention, two support shafts a1b are arranged in parallel, and a plurality of enlarged levers 1.2.3 are alternately attached to different support shafts a, b, respectively. It is rotatably supported on the shaft b, and the horizontal pin ip at the tip of the first stage's expanding lever 1 presses the position near the fulcrum of the next stage's expanding lever 2, and the position of the tip of the bottle 2p is expanded. It is configured. In this way, the plurality of enlargement levers 1.2.. . can be arranged side by side in close proximity, and the enlargement mechanism can be made smaller. Even if you increase the number of expansion levers to increase the expansion rate, the size will only increase by the size of the additional expansion lever. Also, two spindles are always sufficient.

[Brief explanation of drawings]

FIG. 1 is a side view explaining the basic principle of the piezoelectric control valve according to the present invention, FIG. 2 is a perspective view of a conventional lever-type expansion mechanism, and FIG. 3 is a view of the expansion mechanism of the piezoelectric control valve according to the present invention. The front view and FIG. 4 are sectional views taken along line IV-IV' in FIG. In the figure, a and b are the support shafts, 1.2.3 is the expansion lever, and i
p and 2p are pins, 7 is a nozzle needle, 9 is a piezoelectric element, 12 is a spherical recess, 13 is a slit, and 15 is a nozzle.

Claims (1)

[Claims] Two supporting shafts (a) and (b) are arranged in parallel with an interval,
At least two enlarged levers (1), (2), etc. are arranged parallel to each other and perpendicular to the support shafts (a) and (b), and the first enlarged lever (1) is the first enlarged lever. is supported on the support shaft (a) with the tip facing the second support shaft (b), and then
) is pivoted on the second support shaft (b) and its tip is attached to the first support shaft (b).
By pointing toward a), the adjacent expansion levers (1), (2),
... are alternately supported on different support shafts, with the tips facing the other support shaft, and the positions near the free ends of each enlargement lever (1), (2) ... are used to enlarge the adjacent next stage. Engage the lever (2) at a position closer to the shaft support, apply driving force to the valve body with the enlarged lever at the final stage, and move it to the position closer to the shaft support of the first stage enlarged lever (1). A piezoelectric control valve characterized in that it is configured to apply force due to displacement of a piezoelectric element.