JPS5911746B2 - fluid injection valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a fluid injection valve used in an electronically controlled fuel injection device that injects pressurized fluid.

Conventionally, in this type of injection valve, an electric field is applied to a unimorph type piezoelectric element to cause it to expand and contract, thereby displacing a needle mechanically coupled to the piezoelectric element, thereby opening the valve and injecting pressurized fluid. was.

However, in a unimorph type piezoelectric element, the expansion and contraction displacement of the piezoelectric element with respect to the electric field strength is very small, and in order to obtain the displacement (approximately 0.01 mm) to perform the valve function, the electric field strength must be extremely high (several + KV/cm). It is also necessary to increase the length of the piezoelectric element (about 10 cm). For this reason, there are problems such as high voltage insulation treatment, measures to withstand voltage of the piezoelectric element, and increasing the size of the injection valve. Needle, rod, etc.
Valve seats, etc. must be manufactured and assembled with high precision. In the present invention, a movable valve body made of a bimorph type piezoelectric element plate that deforms when a voltage is applied is brought into contact with a valve seat, and only when a voltage is applied to the movable valve body, the valve body deforms and creates a pressure fluid passage. It is an object of the present invention to provide a fluid injection valve that eliminates the drawbacks of conventional devices by having a configuration that injects pressure fluid when opened.

The present invention will be explained below with reference to a first embodiment shown in FIGS. 1 to 3.

Reference numeral 1 designates a first fluid guiding member, and a filter 3 is press-fitted into the inlet portion 2 of the j0 fluid.

Reference numeral 4 designates a second fluid guiding member, at one end of which a valve seat 5 is modified, and at the other end an orifice body T is fixed by a caulking portion 6.

Reference numeral 8 denotes a movable valve body, which in combination with the valve seat 5 constitutes a valve.

The movable valve body 8 is made of, for example, a bimors type piezoelectric element made by bonding two piezoelectric element plates made of lead zirconate titanate porcelain, and has the property of bending when a voltage is applied. Moreover, such a piezoelectric element can obtain a sufficiently flat bending displacement even when a low voltage is applied to a small piezoelectric element. Reference numeral 9 denotes a holding spring that acts to bring the movable valve body 8 into close contact with the valve seat 5, and 10 a lead wire that electrically connects the movable valve body 8 and the connector pin 11.

One leader line 10 is cut in the middle as shown in the figure.
However, in reality, it is not connected to other connector pins as shown in the figure. 12 is a resin cover attached to the first fluid guiding member 1 to keep the connector pin 11 airtight and insulated. and fix it.

13a is a fluid passage formed in the first fluid guiding member 1;
13b is a fluid passage formed in the second fluid guide member 904, 14 is an orifice formed in the orifice body T,
Determine the amount of fluid to be injected.

The operation of the fluid injection valve having the above structure will be explained.

(not shown) When a control voltage 35 from an electronic control device or the like is supplied to the movable valve body 8 via the connector pin 11 and the lead wire 10, the movable valve body 8 bends as shown in FIG. The valve opens by moving away from the seat 5. At that time, the pressure fluid that has been pressurized to a certain pressure in advance flows through the inlet portion 2, the filter 3, the fluid passage 13a on the first fluid guiding member 1 side, the valve seat 5, and the movable valve body. The movable valve body 8 is forced to flow through the gap 8 into the fluid passage 13b on the second fluid guiding member 4 side and is injected from the orifice 14.When the supply of the control voltage is cut off, the movable valve body 8 releases itself as shown in FIG. It returns to a flat shape due to the restoring force of the retaining spring 9.
Since the valve is brought into close contact with the valve seat 5 and the valve is closed, the injection of fluid is stopped. 4 to 6 show a second embodiment of the present invention, in which a fluid passage 131 is provided in the second fluid guiding member 4'.
A central hole 15 and a small hole 16 are provided in the orifice 14, and a valve seat 5'b is carved at one end (8' is a circular movable valve body with a hole in the center, Together with the seat, it forms the valve part.

The movable valve body is made of a bimorph piezoelectric element similar to that of the first embodiment. Reference numeral 17 denotes a fixing pin for fixing the movable valve body g to the second fluid guiding member 1, which passes through the hole of the movable valve body 8' and is fitted into the central hole 15 of the second fluid guiding member 4' (7). are combined.

One of the lead wires 1 is connected to the small hole 16 of the second fluid guiding member 4.
0' is passed through and is closed by the lid 18. Next, the operation will be explained. (not shown) When a control voltage from an electronic control device or the like is supplied to the movable valve body 8 through the connector pin 11' and the lead wire 10', the movable valve body v curves as shown in FIG. The valve opens by moving away from the valve seat. At that time, the pressure fluid flows through the inlet section 2 (filter zone, fluid passages 13f1 and 13b).
', the orifice 14', and the gap between the valve seat 5/ and the movable valve body 8'. When the supply of the control voltage is cut off, the movable valve body 8 returns to its flat shape due to its own restoring force, as shown in FIG. 4, and closes the valve by closely contacting the valve seat 5'. will be stopped. 7 to 9 show a third embodiment of the present invention, in which the first fluid guiding member V'f
) A fluid passage 13a7 and a communication hole 19 are provided at one end, and a filter 3'' is press-fitted into the inlet T.A fluid passage 13b' is provided at the other end of the fluid guide member V, and an orifice is provided. Orifice body 7″ with 14″
t) Closed. Further, a spherical part 20 is provided in the middle of the fluid guide member 5, and a fluid passage groove 21 is provided at the maximum outer circumference of the spherical part 20, and both edges of the fluid passage groove 21 are connected to the valve seat 5.
/9/ While forming the fluid passage groove 21 and the fluid passage 1
A fluid passage hole 22 communicating with the 3-bi is provided. 8/'
is a cylindrical movable valve body, and constitutes a valve with a valve seat 5/'.

The movable valve body r is made of one piezoelectric element plate made of, for example, lead titanate-variconate porcelain, and has the property of expanding outward when a voltage is applied. By making the movable valve body r cylindrical in this way, even if the amount of displacement is small, the movable valve body 8'
A large opening area can be obtained between the circumferential surface and the outer circumferential surface of the spherical part 20. Reference numeral 23 denotes a guide ring for positioning the movable valve body 8/'f), which has a notch 24 for passing fluid.

Reference numeral 25 denotes a housing, one end of which directly fixes the fluid guide member 2, and the other end fixes the fluid guide member Y' via a plate 26.

Next, the operation will be explained. (not shown) When a control voltage from an electronic control device or the like is supplied to the movable valve body W via the connector pin 1Y/ and the lead wire 10I, the movable valve body 8'41 expands as shown in FIG. The valve opens away from the valve seat.At that time, the pressure fluid flows through the inlet 2', filter 3'', and fluid passage 1.
3a'', the communication hole 19, the notch 24, the gap between the valve seat 5'' and the movable valve body 8'5, the fluid passage hole 21, the fluid passage hole 22, the fluid passage 13b, and then the fluid is injected from the orifice 14/. When the supply of the control voltage is cut off, the movable valve body r returns to its original size by its own restoring force as shown in FIG. will be stopped. As described above, the present invention brings a movable valve body made of a piezoelectric element plate that deforms when voltage is applied to the valve seat of a fluid guiding member that forms a valve seat and a fluid passage,
By opening and closing the fluid passage through the valve function of the movable valve body and the valve seat, compared to conventional devices that open and close the valve by displacing a needle connected to a piezoelectric element. If the hydraulic pressure is low (.), sufficient valve function can be obtained with a low voltage, so there is no need for high voltage insulation treatment or measures for the voltage resistance of the piezoelectric element.

In addition, the valve is constructed from a valve seat and a movable valve body without using needles or rods, which simplifies manufacturing and assembly. Furthermore, since the movable valve body can be significantly downsized, the overall size of the injection valve can also be downsized, which has an excellent effect.

[Brief explanation of the drawing]

1 to 3 show a first embodiment of the device of the present invention, FIG. 1 is an overall sectional view, and FIG. 2 is an A-I in FIG. 1.
3 is a cross-sectional view of a main part used to explain the operation, and FIGS. 4 to 6 show a second embodiment of the device of the present invention, and FIG.
The figure is an overall sectional view, Fig. 5 is a side view seen from B in Fig. 4, Fig. 6 is a sectional view of main parts for explaining operation, and Figs.
FIG. 9 shows a third embodiment of the device of the present invention, FIG. 7 is an overall sectional view, FIG. 8 is a C-C note diagram in FIG. 7,
FIG. 9 is a sectional view of a main part used to explain the operation. 1.V.T...first fluid guiding member, 4.4ζ...second fluid guiding member, 5.51-de...valve seat, 8.8'
・r...Movable valve body, 13a, 13i, 13&I...
Fluid passages, 13b, 13d, 13V...fluid passages.

Claims (1)

[Claims] 1. A movable valve body made of a bimorph piezoelectric element plate that deforms when a voltage is applied, a valve seat that comes into contact with the movable valve body, and a fluid guiding member that has a fluid passage for passing pressure fluid, A fluid injection valve characterized in that the fluid passage is opened and closed by a valve function of a valve body and the valve seat.